\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1058\" title=\"Codeforces Beta Round #49 (Div. 2)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"191:192\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1065\" title=\"Tutorial for problems of Codeforces Beta Round #49 (Div.2). All problems now.\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"803:804\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1064\" title=\"Разбор задач Codeforces Beta Round #49(Div. 2)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"802\" resourceName=\"Разбор задач Codeforces Beta Round #49(Div. 2)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/53\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/53/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/53/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/53/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/53/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/53/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/53/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/53/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_4758a65e5deed1d6b14d295050535f0bc1566a8d\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Little Frog</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Once upon a time a little frog whose name was Vasya decided to travel around his home swamp. Overall there are <span class=\"tex-span\"><i>n</i></span> mounds on the swamp, located on one line. The distance between the neighboring mounds is one meter. Vasya wants to visit all the mounds in one day; besides, he wants to visit each one exactly once. For that he makes a route plan, to decide the order in which to jump on the mounds. Vasya can pick any mound as the first one. He thinks it boring to jump two times at the same distance. That's why he wants any two jumps on his route to have different lengths. Help Vasya the Frog and make the plan for him.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The single line contains a number <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">4</sup></span>) which is the number of mounds.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print <span class=\"tex-span\"><i>n</i></span> integers <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>p</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i></span>) which are the frog's route plan. </p><ul> <li> All the <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span>'s should be mutually different. </li><li> All the <span class=\"tex-span\">|<i>p</i><sub class=\"lower-index\"><i>i</i></sub>–<i>p</i><sub class=\"lower-index\"><i>i</i> + 1</sub>|</span>'s should be mutually different (<span class=\"tex-span\">1 ≤ <i>i</i> ≤ <i>n</i> - 1</span>). </li></ul><p>If there are several solutions, output any.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 2 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1 3 2 </pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='b06bfd3490e7ae9dd4bfb22ef9be6e8f'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/yeputons\">yeputons</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/yeputons\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/yeputons\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/yeputons\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/yeputons\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/yeputons\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/yeputons\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/yeputons\" style=\"text-decoration:none;color:black !important;\">yeputons's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1065\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1065\"> Tutorial for problems of Codeforces Beta Round #49 (Div.2). All problems now.\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/yeputons\" title=\"Grandmaster yeputons\" class=\"rated-user user-red\">yeputons</a>,\r\n <span class=\"format-humantime\" title=\"Jan/07/2011 15:35\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">Let's go.<br /><br /><div align=\"center\" class=\"title\">A. Autocomplete</div><br /><div align=\"left\">In this problem you should read the statement and solve in any way. One of the most simple solutions is read string and last visited pages, sort (even bubble source - 100<sup>3</sup> isn't a lot, 3rd power because we need 100 operations to compare two strings), and rundown pages. When we find good string, we should write it and exit.<br />If there are no such one, write source string. 'Goodness' of string is checking with one <i>if</i> (to check lengths and avoid <i>RTE</i>) and <i>for</i>.<br /> <br /><br /><div align=\"center\" class=\"title\">C. Froggy (Little Frog)</div><br /></div>IMHO it's the second difficulty problem. If you cannot see solution just after you saw the statement, you can write brute-force solution (rundown all permutation and check), run it for <i>n=10</i> and see beautiful answer.<br />Answer is <i>1 n 2 (n-1) 3 (n-2) 4 (n-3) ... </i>Let's define two pointers - <i>l</i> and <i>r</i>.<i> </i>In<i> </i>the beginning, the first one will point <span>to 1, and the second one - to n. On odd positions write down <i>l</i> (and increase it), on even - <i>r</i> (and decrease it). Do it while <i>l <= r</i>.<br />Proof is rather easy: every jump is shorter than the previous one.<br /></span><br /><div align=\"center\" class=\"title\"><br />D. Physical education</div><br /><div align=\"left\">This problem is also very easy. The first thing we should learn is moving element from position <i>x</i> to position <i>y (y < x)</i>. Let's move <i>x </i>to position <i>x - 1</i> with one oblivious swap. Then to position <i>x -2</i>. And so on.<br />Now we want to make <i>a<sub>1</sub>=b<sub>1</sub></i>. Find in <i>b</i> element, that equals <i>a1</i> and move it to the first position. Similarly we can make <i>a<sub>2</sub>=b<sub>2</sub></i>. So, we have <i>n</i> steps and at every step we do <i>n - 1</i> swaps at the most. <i>n<=300</i>, so <i>n(n-1)<=89700<10<sup>6</sup></i>.<br /><br /><div align=\"center\" class=\"title\">B. Blog photo</div><br /><div align=\"left\">Due to <a href=\"https://codeforces.com/blog/entry/1059\">bug in GCC</a> I've lost 25 minutes solving this problem. In the end I've used MSVC++.<br />But it was digression, now let's think.<br />The first thing we need to do is fix one side (which are power of two). Because there are two sides and copy-paste is great place for bugs it'll be better to make one more <i>for</i> from 1 to 2 and on the 2nd step swap <i>w</i> and <i>h</i>. It decreases amount of code.<br />Now we know that <i>h=2<sup>x</sup></i>. We need to find such <i>w</i>, that <i>0.8 <= h/w <= 1.25. </i>Solve inequalities for <i>w</i>: <i>h/1.25 <= w <= h/0.8. </i>Because<i> w </i>is integer, it can take any value from <i>ceil(h/1.25) </i>to<i> </i> <i>floor(h/0.8) </i>inclusive. We need to maximize square and <i>h</i> is fixed, so our target is maximize <i>w</i>. We need to let <i>w=floor(h/0.8)</i> and check that it fit borders. If so - relax the answer.<br />It's <i>O(log<sub>2</sub> h)</i> solution.<br />Possible bugs are:<br /><ul><li>You calculate square in 32-bit type or like this: <i>int w = ..., h = ...; long long s = w * h; </i>In this case compiler calculate <i>w * h</i> <b>in 32-bit type first</b>, and then convert it to <i>long long</i>. Solution is <i>long long s = (long long)w * h</i></li><li><i>floor(0.9999999999)=0. </i>The <i>floor</i> function does not correspond with inaccuracy of floating point types. It can be solved either with adding something <i>eps</i> to number before calling <i>floor</i>, or with additional check that difference between <i>floor</i>'s result and source value is not greater than <i>1 - eps</i>.</li><li>p.s. The <i>floor</i> function is up to <b>8-9 times</b> slower that conversion to<i> int</i>.<br /></li></ul><br /><div align=\"center\" class=\"title\">E. Dead ends</div><br /><div align=\"left\">The first thing you should notice - <span> - <i>n <= 10</i>. It means, that we have exponential solution and we can rundown some subsets.<br /><br />Solution is dynamic programming <i>d[m][subm]</i> - number of ways to make connected tree from subgraph <i>m</i> (it's a bit mask) with dead ends <i>subm</i> (it's also a bit mask). Answer is sum of <i>d[2<sup>n</sup>-1][x]</i>, where <i>|x|=k </i>(size of <i>x</i> as a subset is <i>k</i>).<br />Recalculating isn't really hard. For empty subset and subset of two vertexes (either 0 or 1) answer is oblivious. Also you should know that there is no tree with exactly one dead end (it's easy to prove). Now for greater subsets: rundown <i>i</i> from <i>subm</i> - one of dead ends. Cut it off from tree along some edge to <i>b</i> (<i>b</i> shouldn't be a dead end, otherwise we got unconnected graph). Now we have tree with lower count of vertexes and either decreased 1 number of dead ends or with changed <i>i</i> to <i>b</i> (if <i>b</i> had exactly two neighbors). Answer for this tree we know already. In the end of summarizing we should divide answer by <i>k</i> - each tree has been taken as many times, as it has dead ends (<i>k</i>).<br /><br /></span></div></div>p.s. I'll be glad if you tell me my mistakes in English.<br /><br /></div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/53\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 49 (Div. 2)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1484-1065\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1484\",\n blogEntryId: \"1065\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, 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class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"409714\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/szpszp\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/381560/avatar/4038f3db8b18b880.jpg'/> </a>\n <div><a href=\"/profile/szpszp\" title=\"Expert szpszp\" class=\"rated-user user-blue\">szpszp</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/25/2018 12:05\">6 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-409714\" href=\"?#comment-409714\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"409714\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"381560\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-409714\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Could someone help me to explain why we can get correct/unrepeated answer if we add a new point linked by points which belong to the original graph and has number smaller than any leaf node?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-409714 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-409714 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-409714\">\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1075\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"}}},{"rowIdx":277,"cells":{"problem_id":{"kind":"string","value":"53D"},"contest":{"kind":"string","value":"53"},"problem":{"kind":"string","value":"D"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"D. Physical Education"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Physical Education</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya is a school PE teacher. Unlike other PE teachers, Vasya doesn't like it when the students stand in line according to their height. Instead, he demands that the children stand in the following order: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>, where <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> is the height of the <span class=\"tex-span\"><i>i</i></span>-th student in the line and <span class=\"tex-span\"><i>n</i></span> is the number of students in the line. The children find it hard to keep in mind this strange arrangement, and today they formed the line in the following order: <span class=\"tex-span\"><i>b</i><sub class=\"lower-index\">1</sub>, <i>b</i><sub class=\"lower-index\">2</sub>, ..., <i>b</i><sub class=\"lower-index\"><i>n</i></sub></span>, which upset Vasya immensely. Now Vasya wants to rearrange the children so that the resulting order is like this: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>. During each move Vasya can swap two people who stand next to each other in the line. Help Vasya, find the sequence of swaps leading to the arrangement Vasya needs. It is not required to minimize the number of moves.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 300</span>) which is the number of students. The second line contains <span class=\"tex-span\"><i>n</i></span> space-separated integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>) which represent the height of the student occupying the <span class=\"tex-span\"><i>i</i></span>-th place must possess. The third line contains <span class=\"tex-span\"><i>n</i></span> space-separated integers <span class=\"tex-span\"><i>b</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>b</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>) which represent the height of the student occupying the <span class=\"tex-span\"><i>i</i></span>-th place in the initial arrangement. It is possible that some students possess similar heights. It is guaranteed that it is possible to arrange the children in the required order, i.e. <span class=\"tex-span\"><i>a</i></span> and <span class=\"tex-span\"><i>b</i></span> coincide as multisets.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line print an integer <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">0 ≤ <i>k</i> ≤ 10<sup class=\"upper-index\">6</sup></span>) which is the number of moves. It is not required to minimize <span class=\"tex-span\"><i>k</i></span> but it must not exceed <span class=\"tex-span\">10<sup class=\"upper-index\">6</sup></span>. Then print <span class=\"tex-span\"><i>k</i></span> lines each containing two space-separated integers. Line <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span> (<span class=\"tex-span\">1 ≤ <i>p</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i> - 1</span>) means that Vasya should swap students occupying places <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i> + 1</sub></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>1 2 3 2<br/>3 2 1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/>2 3<br/>1 2<br/>3 4<br/>2 3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>1 100500<br/>1 100500<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"8ab932b51e2669d9455c5d3755e99d0d\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"04d8865eeeefdf236386935aa707a6a7be7ef834\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/53\">Codeforces Beta Round 49 (Div. 2)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='8ab932b51e2669d9455c5d3755e99d0d'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/53/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Sortings, orderings\">\r\n sortings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1500\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='8ab932b51e2669d9455c5d3755e99d0d'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"280\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='8ab932b51e2669d9455c5d3755e99d0d'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"280\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1058\" title=\"Codeforces Beta Round #49 (Div. 2)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"191:192\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1065\" title=\"Tutorial for problems of Codeforces Beta Round #49 (Div.2). All problems now.\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"803:804\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1064\" title=\"Разбор задач Codeforces Beta Round #49(Div. 2)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"802\" resourceName=\"Разбор задач Codeforces Beta Round #49(Div. 2)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/53\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/53/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/53/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/53/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/53/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/53/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/53/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/53/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_5e192ca4f26f5890ea6e6cc61207b811034ddf30\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Physical Education</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya is a school PE teacher. Unlike other PE teachers, Vasya doesn't like it when the students stand in line according to their height. Instead, he demands that the children stand in the following order: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>, where <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> is the height of the <span class=\"tex-span\"><i>i</i></span>-th student in the line and <span class=\"tex-span\"><i>n</i></span> is the number of students in the line. The children find it hard to keep in mind this strange arrangement, and today they formed the line in the following order: <span class=\"tex-span\"><i>b</i><sub class=\"lower-index\">1</sub>, <i>b</i><sub class=\"lower-index\">2</sub>, ..., <i>b</i><sub class=\"lower-index\"><i>n</i></sub></span>, which upset Vasya immensely. Now Vasya wants to rearrange the children so that the resulting order is like this: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\">1</sub>, <i>a</i><sub class=\"lower-index\">2</sub>, ..., <i>a</i><sub class=\"lower-index\"><i>n</i></sub></span>. During each move Vasya can swap two people who stand next to each other in the line. Help Vasya, find the sequence of swaps leading to the arrangement Vasya needs. It is not required to minimize the number of moves.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 300</span>) which is the number of students. The second line contains <span class=\"tex-span\"><i>n</i></span> space-separated integers <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>) which represent the height of the student occupying the <span class=\"tex-span\"><i>i</i></span>-th place must possess. The third line contains <span class=\"tex-span\"><i>n</i></span> space-separated integers <span class=\"tex-span\"><i>b</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>b</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">9</sup></span>) which represent the height of the student occupying the <span class=\"tex-span\"><i>i</i></span>-th place in the initial arrangement. It is possible that some students possess similar heights. It is guaranteed that it is possible to arrange the children in the required order, i.e. <span class=\"tex-span\"><i>a</i></span> and <span class=\"tex-span\"><i>b</i></span> coincide as multisets.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line print an integer <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">0 ≤ <i>k</i> ≤ 10<sup class=\"upper-index\">6</sup></span>) which is the number of moves. It is not required to minimize <span class=\"tex-span\"><i>k</i></span> but it must not exceed <span class=\"tex-span\">10<sup class=\"upper-index\">6</sup></span>. Then print <span class=\"tex-span\"><i>k</i></span> lines each containing two space-separated integers. Line <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span>, <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub> + 1</span> (<span class=\"tex-span\">1 ≤ <i>p</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i> - 1</span>) means that Vasya should swap students occupying places <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>p</i><sub class=\"lower-index\"><i>i</i> + 1</sub></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />1 2 3 2<br />3 2 1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br />2 3<br />1 2<br />3 4<br />2 3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />1 100500<br />1 100500<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", \"//codeforces.org/s/73366\");\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:53</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a 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href=\"/profile/yeputons\">yeputons</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/yeputons\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/yeputons\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/yeputons\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/yeputons\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/yeputons\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/yeputons\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/yeputons\" style=\"text-decoration:none;color:black !important;\">yeputons's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1065\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1065\"> Tutorial for problems of Codeforces Beta Round #49 (Div.2). All problems now.\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/yeputons\" title=\"Grandmaster yeputons\" class=\"rated-user user-red\">yeputons</a>,\r\n <span class=\"format-humantime\" title=\"Jan/07/2011 15:35\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">Let's go.<br /><br /><div align=\"center\" class=\"title\">A. Autocomplete</div><br /><div align=\"left\">In this problem you should read the statement and solve in any way. One of the most simple solutions is read string and last visited pages, sort (even bubble source - 100<sup>3</sup> isn't a lot, 3rd power because we need 100 operations to compare two strings), and rundown pages. When we find good string, we should write it and exit.<br />If there are no such one, write source string. 'Goodness' of string is checking with one <i>if</i> (to check lengths and avoid <i>RTE</i>) and <i>for</i>.<br /> <br /><br /><div align=\"center\" class=\"title\">C. Froggy (Little Frog)</div><br /></div>IMHO it's the second difficulty problem. If you cannot see solution just after you saw the statement, you can write brute-force solution (rundown all permutation and check), run it for <i>n=10</i> and see beautiful answer.<br />Answer is <i>1 n 2 (n-1) 3 (n-2) 4 (n-3) ... </i>Let's define two pointers - <i>l</i> and <i>r</i>.<i> </i>In<i> </i>the beginning, the first one will point <span>to 1, and the second one - to n. On odd positions write down <i>l</i> (and increase it), on even - <i>r</i> (and decrease it). Do it while <i>l <= r</i>.<br />Proof is rather easy: every jump is shorter than the previous one.<br /></span><br /><div align=\"center\" class=\"title\"><br />D. Physical education</div><br /><div align=\"left\">This problem is also very easy. The first thing we should learn is moving element from position <i>x</i> to position <i>y (y < x)</i>. Let's move <i>x </i>to position <i>x - 1</i> with one oblivious swap. Then to position <i>x -2</i>. And so on.<br />Now we want to make <i>a<sub>1</sub>=b<sub>1</sub></i>. Find in <i>b</i> element, that equals <i>a1</i> and move it to the first position. Similarly we can make <i>a<sub>2</sub>=b<sub>2</sub></i>. So, we have <i>n</i> steps and at every step we do <i>n - 1</i> swaps at the most. <i>n<=300</i>, so <i>n(n-1)<=89700<10<sup>6</sup></i>.<br /><br /><div align=\"center\" class=\"title\">B. Blog photo</div><br /><div align=\"left\">Due to <a href=\"https://codeforces.com/blog/entry/1059\">bug in GCC</a> I've lost 25 minutes solving this problem. In the end I've used MSVC++.<br />But it was digression, now let's think.<br />The first thing we need to do is fix one side (which are power of two). Because there are two sides and copy-paste is great place for bugs it'll be better to make one more <i>for</i> from 1 to 2 and on the 2nd step swap <i>w</i> and <i>h</i>. It decreases amount of code.<br />Now we know that <i>h=2<sup>x</sup></i>. We need to find such <i>w</i>, that <i>0.8 <= h/w <= 1.25. </i>Solve inequalities for <i>w</i>: <i>h/1.25 <= w <= h/0.8. </i>Because<i> w </i>is integer, it can take any value from <i>ceil(h/1.25) </i>to<i> </i> <i>floor(h/0.8) </i>inclusive. We need to maximize square and <i>h</i> is fixed, so our target is maximize <i>w</i>. We need to let <i>w=floor(h/0.8)</i> and check that it fit borders. If so - relax the answer.<br />It's <i>O(log<sub>2</sub> h)</i> solution.<br />Possible bugs are:<br /><ul><li>You calculate square in 32-bit type or like this: <i>int w = ..., h = ...; long long s = w * h; </i>In this case compiler calculate <i>w * h</i> <b>in 32-bit type first</b>, and then convert it to <i>long long</i>. Solution is <i>long long s = (long long)w * h</i></li><li><i>floor(0.9999999999)=0. </i>The <i>floor</i> function does not correspond with inaccuracy of floating point types. It can be solved either with adding something <i>eps</i> to number before calling <i>floor</i>, or with additional check that difference between <i>floor</i>'s result and source value is not greater than <i>1 - eps</i>.</li><li>p.s. The <i>floor</i> function is up to <b>8-9 times</b> slower that conversion to<i> int</i>.<br /></li></ul><br /><div align=\"center\" class=\"title\">E. Dead ends</div><br /><div align=\"left\">The first thing you should notice - <span> - <i>n <= 10</i>. It means, that we have exponential solution and we can rundown some subsets.<br /><br />Solution is dynamic programming <i>d[m][subm]</i> - number of ways to make connected tree from subgraph <i>m</i> (it's a bit mask) with dead ends <i>subm</i> (it's also a bit mask). Answer is sum of <i>d[2<sup>n</sup>-1][x]</i>, where <i>|x|=k </i>(size of <i>x</i> as a subset is <i>k</i>).<br />Recalculating isn't really hard. For empty subset and subset of two vertexes (either 0 or 1) answer is oblivious. Also you should know that there is no tree with exactly one dead end (it's easy to prove). Now for greater subsets: rundown <i>i</i> from <i>subm</i> - one of dead ends. Cut it off from tree along some edge to <i>b</i> (<i>b</i> shouldn't be a dead end, otherwise we got unconnected graph). Now we have tree with lower count of vertexes and either decreased 1 number of dead ends or with changed <i>i</i> to <i>b</i> (if <i>b</i> had exactly two neighbors). Answer for this tree we know already. In the end of summarizing we should divide answer by <i>k</i> - each tree has been taken as many times, as it has dead ends (<i>k</i>).<br /><br /></span></div></div>p.s. I'll be glad if you tell me my mistakes in English.<br /><br /></div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/53\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 49 (Div. 2)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1484-1065\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1484\",\n blogEntryId: \"1065\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+49\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 49</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1065\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+37</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1065\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/yeputons\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/yeputons\">\n yeputons\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/07/2011 15:35\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1065#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1065#comments\">\n 2\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1075\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (1)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"409714\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/szpszp\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/381560/avatar/4038f3db8b18b880.jpg'/> </a>\n <div><a href=\"/profile/szpszp\" title=\"Expert szpszp\" class=\"rated-user user-blue\">szpszp</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/25/2018 12:05\">6 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-409714\" href=\"?#comment-409714\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"409714\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"381560\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-409714\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Could someone help me to explain why we can get correct/unrepeated answer if we add a new point linked by points which belong to the original graph and has number smaller than any leaf node?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-409714 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-409714 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-409714\">\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1075\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input 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Dead Ends"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Dead Ends</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>5 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Life in Bertown has become hard. The city has too many roads and the government spends too much to maintain them. There are <span class=\"tex-span\"><i>n</i></span> junctions and <span class=\"tex-span\"><i>m</i></span> two way roads, at which one can get from each junction to any other one. The mayor wants to close some roads so that the number of roads left totaled to <span class=\"tex-span\"><i>n</i> - 1</span> roads and it were still possible to get from each junction to any other one. Besides, the mayor is concerned with the number of dead ends which are the junctions from which only one road goes. There shouldn't be too many or too few junctions. Having discussed the problem, the mayor and his assistants decided that after the roads are closed, the road map should contain exactly <span class=\"tex-span\"><i>k</i></span> dead ends. Your task is to count the number of different ways of closing the roads at which the following conditions are met: </p><ul> <li> There are exactly <span class=\"tex-span\"><i>n</i> - 1</span> roads left. </li><li> It is possible to get from each junction to any other one. </li><li> There are exactly <span class=\"tex-span\"><i>k</i></span> dead ends on the resulting map. </li></ul><p>Two ways are considered different if there is a road that is closed in the first way, and is open in the second one.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 10, <i>n</i> - 1 ≤ <i>m</i> ≤ <i>n</i>·(<i>n</i> - 1) / 2, 2 ≤ <i>k</i> ≤ <i>n</i> - 1</span>) which represent the number of junctions, roads and dead ends correspondingly. Then follow <span class=\"tex-span\"><i>m</i></span> lines each containing two different integers <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">1 ≤ <i>v</i><sub class=\"lower-index\">1</sub>, <i>v</i><sub class=\"lower-index\">2</sub> ≤ <i>n</i>, <i>v</i><sub class=\"lower-index\">1</sub> ≠ <i>v</i><sub class=\"lower-index\">2</sub></span>) which represent the number of junctions connected by another road. There can be no more than one road between every pair of junctions. The junctions are numbered with integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. It is guaranteed that it is possible to get from each junction to any other one along the original roads.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number — the required number of ways.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3 2<br/>1 2<br/>2 3<br/>1 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 6 2<br/>1 2<br/>2 3<br/>3 4<br/>4 1<br/>1 3<br/>2 4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>12<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 6 3<br/>1 2<br/>2 3<br/>3 4<br/>4 1<br/>1 3<br/>2 4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"7adeef3e40fbb971f9700a53d26e0ff9\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"04d8865eeeefdf236386935aa707a6a7be7ef834\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/53\">Codeforces Beta Round 49 (Div. 2)</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='7adeef3e40fbb971f9700a53d26e0ff9'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/53/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Bitmasks\">\r\n bitmasks\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2500\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7adeef3e40fbb971f9700a53d26e0ff9'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"281\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='7adeef3e40fbb971f9700a53d26e0ff9'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"281\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1058\" title=\"Codeforces Beta Round #49 (Div. 2)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"191:192\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1065\" title=\"Tutorial for problems of Codeforces Beta Round #49 (Div.2). All problems now.\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"803:804\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1064\" title=\"Разбор задач Codeforces Beta Round #49(Div. 2)\" target=\"_blank\">Tutorial #2 <span class=\"resource-locale\">(ru)</span></a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"802\" resourceName=\"Разбор задач Codeforces Beta Round #49(Div. 2)\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/53\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/53/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/53/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/53/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/53/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/53/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/53/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/53/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_a8e76d853fcc4962c5b5e1d2f1b7a80fa8d077d2\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Dead Ends</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>5 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Life in Bertown has become hard. The city has too many roads and the government spends too much to maintain them. There are <span class=\"tex-span\"><i>n</i></span> junctions and <span class=\"tex-span\"><i>m</i></span> two way roads, at which one can get from each junction to any other one. The mayor wants to close some roads so that the number of roads left totaled to <span class=\"tex-span\"><i>n</i> - 1</span> roads and it were still possible to get from each junction to any other one. Besides, the mayor is concerned with the number of dead ends which are the junctions from which only one road goes. There shouldn't be too many or too few junctions. Having discussed the problem, the mayor and his assistants decided that after the roads are closed, the road map should contain exactly <span class=\"tex-span\"><i>k</i></span> dead ends. Your task is to count the number of different ways of closing the roads at which the following conditions are met: </p><ul> <li> There are exactly <span class=\"tex-span\"><i>n</i> - 1</span> roads left. </li><li> It is possible to get from each junction to any other one. </li><li> There are exactly <span class=\"tex-span\"><i>k</i></span> dead ends on the resulting map. </li></ul><p>Two ways are considered different if there is a road that is closed in the first way, and is open in the second one.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three integers <span class=\"tex-span\"><i>n</i></span>, <span class=\"tex-span\"><i>m</i></span> and <span class=\"tex-span\"><i>k</i></span> (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 10, <i>n</i> - 1 ≤ <i>m</i> ≤ <i>n</i>·(<i>n</i> - 1) / 2, 2 ≤ <i>k</i> ≤ <i>n</i> - 1</span>) which represent the number of junctions, roads and dead ends correspondingly. Then follow <span class=\"tex-span\"><i>m</i></span> lines each containing two different integers <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">1</sub></span> and <span class=\"tex-span\"><i>v</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">1 ≤ <i>v</i><sub class=\"lower-index\">1</sub>, <i>v</i><sub class=\"lower-index\">2</sub> ≤ <i>n</i>, <i>v</i><sub class=\"lower-index\">1</sub> ≠ <i>v</i><sub class=\"lower-index\">2</sub></span>) which represent the number of junctions connected by another road. There can be no more than one road between every pair of junctions. The junctions are numbered with integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. It is guaranteed that it is possible to get from each junction to any other one along the original roads.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number — the required number of ways.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>3 3 2<br />1 2<br />2 3<br />1 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 6 2<br />1 2<br />2 3<br />3 4<br />4 1<br />1 3<br />2 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>12<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4 6 3<br />1 2<br />2 3<br />3 4<br />4 1<br />1 3<br />2 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", \"//codeforces.org/s/73366\");\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:53</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a 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href=\"/profile/yeputons\">yeputons</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/yeputons\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/yeputons\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/yeputons\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/yeputons\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/yeputons\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/yeputons\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/yeputons\" style=\"text-decoration:none;color:black !important;\">yeputons's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1065\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1065\"> Tutorial for problems of Codeforces Beta Round #49 (Div.2). All problems now.\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/yeputons\" title=\"Grandmaster yeputons\" class=\"rated-user user-red\">yeputons</a>,\r\n <span class=\"format-humantime\" title=\"Jan/07/2011 15:35\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\">Let's go.<br /><br /><div align=\"center\" class=\"title\">A. Autocomplete</div><br /><div align=\"left\">In this problem you should read the statement and solve in any way. One of the most simple solutions is read string and last visited pages, sort (even bubble source - 100<sup>3</sup> isn't a lot, 3rd power because we need 100 operations to compare two strings), and rundown pages. When we find good string, we should write it and exit.<br />If there are no such one, write source string. 'Goodness' of string is checking with one <i>if</i> (to check lengths and avoid <i>RTE</i>) and <i>for</i>.<br /> <br /><br /><div align=\"center\" class=\"title\">C. Froggy (Little Frog)</div><br /></div>IMHO it's the second difficulty problem. If you cannot see solution just after you saw the statement, you can write brute-force solution (rundown all permutation and check), run it for <i>n=10</i> and see beautiful answer.<br />Answer is <i>1 n 2 (n-1) 3 (n-2) 4 (n-3) ... </i>Let's define two pointers - <i>l</i> and <i>r</i>.<i> </i>In<i> </i>the beginning, the first one will point <span>to 1, and the second one - to n. On odd positions write down <i>l</i> (and increase it), on even - <i>r</i> (and decrease it). Do it while <i>l <= r</i>.<br />Proof is rather easy: every jump is shorter than the previous one.<br /></span><br /><div align=\"center\" class=\"title\"><br />D. Physical education</div><br /><div align=\"left\">This problem is also very easy. The first thing we should learn is moving element from position <i>x</i> to position <i>y (y < x)</i>. Let's move <i>x </i>to position <i>x - 1</i> with one oblivious swap. Then to position <i>x -2</i>. And so on.<br />Now we want to make <i>a<sub>1</sub>=b<sub>1</sub></i>. Find in <i>b</i> element, that equals <i>a1</i> and move it to the first position. Similarly we can make <i>a<sub>2</sub>=b<sub>2</sub></i>. So, we have <i>n</i> steps and at every step we do <i>n - 1</i> swaps at the most. <i>n<=300</i>, so <i>n(n-1)<=89700<10<sup>6</sup></i>.<br /><br /><div align=\"center\" class=\"title\">B. Blog photo</div><br /><div align=\"left\">Due to <a href=\"https://codeforces.com/blog/entry/1059\">bug in GCC</a> I've lost 25 minutes solving this problem. In the end I've used MSVC++.<br />But it was digression, now let's think.<br />The first thing we need to do is fix one side (which are power of two). Because there are two sides and copy-paste is great place for bugs it'll be better to make one more <i>for</i> from 1 to 2 and on the 2nd step swap <i>w</i> and <i>h</i>. It decreases amount of code.<br />Now we know that <i>h=2<sup>x</sup></i>. We need to find such <i>w</i>, that <i>0.8 <= h/w <= 1.25. </i>Solve inequalities for <i>w</i>: <i>h/1.25 <= w <= h/0.8. </i>Because<i> w </i>is integer, it can take any value from <i>ceil(h/1.25) </i>to<i> </i> <i>floor(h/0.8) </i>inclusive. We need to maximize square and <i>h</i> is fixed, so our target is maximize <i>w</i>. We need to let <i>w=floor(h/0.8)</i> and check that it fit borders. If so - relax the answer.<br />It's <i>O(log<sub>2</sub> h)</i> solution.<br />Possible bugs are:<br /><ul><li>You calculate square in 32-bit type or like this: <i>int w = ..., h = ...; long long s = w * h; </i>In this case compiler calculate <i>w * h</i> <b>in 32-bit type first</b>, and then convert it to <i>long long</i>. Solution is <i>long long s = (long long)w * h</i></li><li><i>floor(0.9999999999)=0. </i>The <i>floor</i> function does not correspond with inaccuracy of floating point types. It can be solved either with adding something <i>eps</i> to number before calling <i>floor</i>, or with additional check that difference between <i>floor</i>'s result and source value is not greater than <i>1 - eps</i>.</li><li>p.s. The <i>floor</i> function is up to <b>8-9 times</b> slower that conversion to<i> int</i>.<br /></li></ul><br /><div align=\"center\" class=\"title\">E. Dead ends</div><br /><div align=\"left\">The first thing you should notice - <span> - <i>n <= 10</i>. It means, that we have exponential solution and we can rundown some subsets.<br /><br />Solution is dynamic programming <i>d[m][subm]</i> - number of ways to make connected tree from subgraph <i>m</i> (it's a bit mask) with dead ends <i>subm</i> (it's also a bit mask). Answer is sum of <i>d[2<sup>n</sup>-1][x]</i>, where <i>|x|=k </i>(size of <i>x</i> as a subset is <i>k</i>).<br />Recalculating isn't really hard. For empty subset and subset of two vertexes (either 0 or 1) answer is oblivious. Also you should know that there is no tree with exactly one dead end (it's easy to prove). Now for greater subsets: rundown <i>i</i> from <i>subm</i> - one of dead ends. Cut it off from tree along some edge to <i>b</i> (<i>b</i> shouldn't be a dead end, otherwise we got unconnected graph). Now we have tree with lower count of vertexes and either decreased 1 number of dead ends or with changed <i>i</i> to <i>b</i> (if <i>b</i> had exactly two neighbors). Answer for this tree we know already. In the end of summarizing we should divide answer by <i>k</i> - each tree has been taken as many times, as it has dead ends (<i>k</i>).<br /><br /></span></div></div>p.s. I'll be glad if you tell me my mistakes in English.<br /><br /></div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/53\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 49 (Div. 2)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1484-1065\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1484\",\n blogEntryId: \"1065\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+49\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 49</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=tutorial\" class=\"tag notice\" style=\"text-decoration: none;\">tutorial</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1065\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+37</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1065\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/yeputons\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/yeputons\">\n yeputons\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/07/2011 15:35\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1065#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1065#comments\">\n 2\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1075\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (1)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"409714\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/szpszp\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/381560/avatar/4038f3db8b18b880.jpg'/> </a>\n <div><a href=\"/profile/szpszp\" title=\"Expert szpszp\" class=\"rated-user user-blue\">szpszp</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/25/2018 12:05\">6 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-409714\" href=\"?#comment-409714\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"409714\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"381560\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-409714\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Could someone help me to explain why we can get correct/unrepeated answer if we add a new point linked by points which belong to the original graph and has number smaller than any leaf node?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-409714 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-409714 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-409714\">\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1075\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input 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Presents"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Presents</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Hedgehog likes to give presents to his friend, but no less he likes to receive them.</p><p>Having received another present today, the Hedgehog suddenly understood that he has no place to put it as there was no room left on the special shelf in the cupboard. He will have to choose another shelf, but which one should he choose, how large should it be?</p><p>In order to get to know this, the Hedgehog asks you to write him a program that will count the estimated number of presents that he will receive during the following <span class=\"tex-span\"><i>N</i></span> days. Besides, he is guided by the principle: </p><ul> <li> on each holiday day the Hedgehog will necessarily receive a present, </li><li> he receives presents at least every <span class=\"tex-span\"><i>K</i></span> days (i.e., if he received a present on the <span class=\"tex-span\"><i>i</i></span>-th day, he will receive the next present no later than on the <span class=\"tex-span\"><i>i</i> + <i>K</i></span>-th day). </li></ul> <p>For the given <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>K</i></span>, as well as the list of holidays among the following <span class=\"tex-span\"><i>N</i></span> days count the minimal number of presents that could be given to the Hedgehog. The number of today's day is zero, and you should regard today's present as already given (i.e., you shouldn't count it in the answer).</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>K</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 365</span>, <span class=\"tex-span\">1 ≤ <i>K</i> ≤ <i>N</i></span>).</p><p>The second line contains a number <span class=\"tex-span\"><i>C</i></span> which represents the number of holidays (<span class=\"tex-span\">0 ≤ <i>C</i> ≤ <i>N</i></span>). Then in the same line follow <span class=\"tex-span\"><i>C</i></span> numbers ranging from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>N</i></span> which are the numbers of holiday days. The numbers are given in the increasing order, without repeating numbers among them.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number — the minimal number of presents the Hedgehog will receive over the following <span class=\"tex-span\"><i>N</i></span> days.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 2<br/>1 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>10 1<br/>3 6 7 8<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>10</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"e6532e23d981121fdb439c463e11649a\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"d5d8da0ccc5d8f6f652c562154ed763cebdcc2c5\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/54\">Codeforces Beta Round 50</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='e6532e23d981121fdb439c463e11649a'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/54/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1300\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='e6532e23d981121fdb439c463e11649a'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"282\"/>\r\n 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style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1087\" title=\"Codeforces Beta Round #50: Разбор задачи D\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"807:808\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1088\" title=\"Codeforces Beta Round #50: Editorial for problem C\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"809:810\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div 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\"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_eab8f1c7da981afd9d353b073d45f5676bcbd36b\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Presents</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Hedgehog likes to give presents to his friend, but no less he likes to receive them.</p><p>Having received another present today, the Hedgehog suddenly understood that he has no place to put it as there was no room left on the special shelf in the cupboard. He will have to choose another shelf, but which one should he choose, how large should it be?</p><p>In order to get to know this, the Hedgehog asks you to write him a program that will count the estimated number of presents that he will receive during the following <span class=\"tex-span\"><i>N</i></span> days. Besides, he is guided by the principle: </p><ul> <li> on each holiday day the Hedgehog will necessarily receive a present, </li><li> he receives presents at least every <span class=\"tex-span\"><i>K</i></span> days (i.e., if he received a present on the <span class=\"tex-span\"><i>i</i></span>-th day, he will receive the next present no later than on the <span class=\"tex-span\"><i>i</i> + <i>K</i></span>-th day). </li></ul> <p>For the given <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>K</i></span>, as well as the list of holidays among the following <span class=\"tex-span\"><i>N</i></span> days count the minimal number of presents that could be given to the Hedgehog. The number of today's day is zero, and you should regard today's present as already given (i.e., you shouldn't count it in the answer).</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integers <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>K</i></span> (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 365</span>, <span class=\"tex-span\">1 ≤ <i>K</i> ≤ <i>N</i></span>).</p><p>The second line contains a number <span class=\"tex-span\"><i>C</i></span> which represents the number of holidays (<span class=\"tex-span\">0 ≤ <i>C</i> ≤ <i>N</i></span>). Then in the same line follow <span class=\"tex-span\"><i>C</i></span> numbers ranging from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>N</i></span> which are the numbers of holiday days. The numbers are given in the increasing order, without repeating numbers among them.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number — the minimal number of presents the Hedgehog will receive over the following <span class=\"tex-span\"><i>N</i></span> days.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 2<br />1 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>10 1<br />3 6 7 8<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>10</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='9473e10add7088b4f8e4b8826329f140'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" 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href=\"/profile/e-maxx\">e-maxx</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/e-maxx\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/e-maxx\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/e-maxx\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/e-maxx\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/e-maxx\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/e-maxx\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/e-maxx\" style=\"text-decoration:none;color:black !important;\">e-maxx's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1085\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1085\"> Codeforces Beta Round #50: Editorial for problem E\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/e-maxx\" title=\"International Master e-maxx\" class=\"rated-user user-orange\">e-maxx</a>,\r\n <span class=\"format-humantime\" title=\"Jan/11/2011 14:06\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><img src=\"/predownloaded/60/74/6074907f7dc69a9479975e89f95f7a1008e34a3d.png\" style=\"float: right;max-width: 100.0%;max-height: 100.0%;\" /></p><p><br /></p><p>The most important step on the way to solve this problem - is to understand that it's enough to consider only such rotations of the polygon, that one of its sides lies on the side of the room.<br /><br />Let's try to understand this fact. Suppose that the fact is wrong, and there exists such a position of vacuum cleaner, that neither of its sides lies on the side of the room. Denote as <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> the numbers of vertices that lie on the room sides. It's easy to understand that the polygon form between vertices <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> doesn't make any sense itself: for each rotation we can see that from the area of triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> some constant area is subtracted, while the concrete value of this constant depends on the polygon form.<br /><br />That's why we see that the polygon form doesn't influence on anything (if we have fixed numbers <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>), and we have just to minimize the area of right-angled triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>. But, taking into account that its hypotenuse is a constant, it's easy to see that the minimum is reached in borderline cases: i.e. when one of the polygon sides lies on the room side.<br /><br />So, we've proved the fact. Then we have to invent fast enough solution. We have already obtained an <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> solution: iterate over all sides of the polygon (i.e. iterating over all possible <span class=\"tex-span\"><i>i</i></span>), mentally push it to one side of the room, then find the threshold point <span class=\"tex-span\"><i>j</i></span>, then calculate answer for given <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>. Let's learn how to do these both things in <span class=\"tex-span\"><i>O</i>(1)</span>.<br /><br />In order to do the first thing (finding <span class=\"tex-span\"><i>j</i></span>) we can use a method of moving pointer: if we iterate over <span class=\"tex-span\"><i>i</i></span> in the same order as in the input file, then we can just maintain the right value of <span class=\"tex-span\"><i>j</i></span> (i.e. when we move from <span class=\"tex-span\"><i>i</i></span> to <span class=\"tex-span\"><i>i</i> + 1</span> we have to increase <span class=\"tex-span\"><i>j</i></span> several times, while it is getting further and further).<br /><br />In order to do the second thing (the area calculation) we have to do some precalculation. For example, we can find the mass center <span class=\"tex-span\"><i>Q</i></span> of the vacuum cleaner, and pre-calculate all partial sums <span class=\"tex-span\"><i>S</i>[<i>i</i>]</span> - sums of all triangles <span class=\"tex-span\"><i>QP</i>[<i>j</i> - 1]<i>P</i>[<i>j</i>]</span> for all <span class=\"tex-span\"><i>j</i> ≤ <i>i</i></span>. After this precalculation we can get the answer for every <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in <span class=\"tex-span\"><i>O</i>(1)</span> as a combination of difference of two values from <span class=\"tex-span\"><i>S</i>[]</span> and two triangles' areas: <span class=\"tex-span\"><i>QP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> and <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>.<br /><br /></p></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/54\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 50</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-123-1085\").click(function() {\n 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none;\">computational geometry</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=geometry\" class=\"tag notice\" style=\"text-decoration: none;\">geometry</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1085\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+19</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1085\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/e-maxx\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/e-maxx\">\n e-maxx\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/11/2011 14:06\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1085#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1085#comments\">\n 0\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1095\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (0)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n <br/>\r\n\r\n<div id=\"editBox-1095\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 0.5em;left:4px;display: none;\">\r\n <input type=\"radio\" name=\"locale\" value=\"en\"><span style=\"font-size: 1.2rem;position: relative; bottom: 3px;\">In English</span>\r\n <input style=\"margin-left:1em\" 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Cutting Jigsaw Puzzle"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Cutting Jigsaw Puzzle</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Hedgehog recently remembered one of his favorite childhood activities, — solving puzzles, and got into it with new vigor. He would sit day in, day out with his friend buried into thousands of tiny pieces of the picture, looking for the required items one by one.</p><p>Soon the Hedgehog came up with a brilliant idea: instead of buying ready-made puzzles, one can take his own large piece of paper with some picture and cut it into many small rectangular pieces, then mix them and solve the resulting puzzle, trying to piece together the picture. The resulting task is even more challenging than the classic puzzle: now all the fragments have the same rectangular shape, and one can assemble the puzzle only relying on the picture drawn on the pieces.</p><p>All puzzle pieces turn out to be of the same size <span class=\"tex-span\"><i>X</i> × <i>Y</i></span>, because the picture is cut first by horizontal cuts with the pitch of <span class=\"tex-span\"><i>X</i></span>, then with vertical cuts with the pitch of <span class=\"tex-span\"><i>Y</i></span>. If we denote the initial size of the picture as <span class=\"tex-span\"><i>A</i> × <i>B</i></span>, then <span class=\"tex-span\"><i>A</i></span> must be divisible by <span class=\"tex-span\"><i>X</i></span> and <span class=\"tex-span\"><i>B</i></span> must be divisible by <span class=\"tex-span\"><i>Y</i></span> (<span class=\"tex-span\"><i>X</i></span> and <span class=\"tex-span\"><i>Y</i></span> are integer numbers). </p><p>However, not every such cutting of the picture will result in a <span class=\"tex-font-style-bf\">good</span> puzzle. The Hedgehog finds a puzzle good if no two pieces in it are the same (It is <span class=\"tex-font-style-bf\">allowed to rotate</span> the pieces when comparing them, but it is forbidden to turn them over). </p><p>Your task is to count for a given picture the number of good puzzles that you can make from it, and also to find the puzzle with the minimal piece size.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two numbers <span class=\"tex-span\"><i>A</i></span> and <span class=\"tex-span\"><i>B</i></span> which are the sizes of the picture. They are positive integers not exceeding 20.</p><p>Then follow <span class=\"tex-span\"><i>A</i></span> lines containing <span class=\"tex-span\"><i>B</i></span> symbols each, describing the actual picture. The lines only contain uppercase English letters.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line print the number of possible good puzzles (in other words, the number of pairs <span class=\"tex-span\">(<i>X</i>, <i>Y</i>)</span> such that the puzzle with the corresponding element sizes will be good). This number should always be positive, because the whole picture is a good puzzle itself. </p><p>In the second line print two numbers — the sizes <span class=\"tex-span\"><i>X</i></span> and <span class=\"tex-span\"><i>Y</i></span> of the smallest possible element among all good puzzles. The comparison is made firstly by the area <span class=\"tex-span\"><i>XY</i></span> of one element and secondly — by the length <span class=\"tex-span\"><i>X</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 4<br/>ABDC<br/>ABDC<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/>2 1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 6<br/>ABCCBA<br/>ABCCBA<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/>2 6<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>The picture in the first sample test has the following good puzzles: <span class=\"tex-span\">(2, 1)</span>, <span class=\"tex-span\">(2, 2)</span>, <span class=\"tex-span\">(2, 4)</span>.</p></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"5db9dc2a8b2a033dd76f37e034cdbb80\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"d5d8da0ccc5d8f6f652c562154ed763cebdcc2c5\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/54\">Codeforces Beta Round 50</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='5db9dc2a8b2a033dd76f37e034cdbb80'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/54/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Hashing, hashtables\">\r\n hashing\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1800\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='5db9dc2a8b2a033dd76f37e034cdbb80'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"283\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='5db9dc2a8b2a033dd76f37e034cdbb80'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"283\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1083\" title=\"Codeforces Beta Round #50\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"193:194\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1085\" title=\"Codeforces Beta Round #50: Editorial for problem E\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"805:806\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1087\" title=\"Codeforces Beta Round #50: Разбор задачи D\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"807:808\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1088\" title=\"Codeforces Beta Round #50: Editorial for problem C\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"809:810\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/54\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/54/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/54/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/54/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/54/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/54/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/54/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/54/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_2dd7dcbec8ba940fdcc316333059edf3e46406a8\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Cutting Jigsaw Puzzle</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Hedgehog recently remembered one of his favorite childhood activities, — solving puzzles, and got into it with new vigor. He would sit day in, day out with his friend buried into thousands of tiny pieces of the picture, looking for the required items one by one.</p><p>Soon the Hedgehog came up with a brilliant idea: instead of buying ready-made puzzles, one can take his own large piece of paper with some picture and cut it into many small rectangular pieces, then mix them and solve the resulting puzzle, trying to piece together the picture. The resulting task is even more challenging than the classic puzzle: now all the fragments have the same rectangular shape, and one can assemble the puzzle only relying on the picture drawn on the pieces.</p><p>All puzzle pieces turn out to be of the same size <span class=\"tex-span\"><i>X</i> × <i>Y</i></span>, because the picture is cut first by horizontal cuts with the pitch of <span class=\"tex-span\"><i>X</i></span>, then with vertical cuts with the pitch of <span class=\"tex-span\"><i>Y</i></span>. If we denote the initial size of the picture as <span class=\"tex-span\"><i>A</i> × <i>B</i></span>, then <span class=\"tex-span\"><i>A</i></span> must be divisible by <span class=\"tex-span\"><i>X</i></span> and <span class=\"tex-span\"><i>B</i></span> must be divisible by <span class=\"tex-span\"><i>Y</i></span> (<span class=\"tex-span\"><i>X</i></span> and <span class=\"tex-span\"><i>Y</i></span> are integer numbers). </p><p>However, not every such cutting of the picture will result in a <span class=\"tex-font-style-bf\">good</span> puzzle. The Hedgehog finds a puzzle good if no two pieces in it are the same (It is <span class=\"tex-font-style-bf\">allowed to rotate</span> the pieces when comparing them, but it is forbidden to turn them over). </p><p>Your task is to count for a given picture the number of good puzzles that you can make from it, and also to find the puzzle with the minimal piece size.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two numbers <span class=\"tex-span\"><i>A</i></span> and <span class=\"tex-span\"><i>B</i></span> which are the sizes of the picture. They are positive integers not exceeding 20.</p><p>Then follow <span class=\"tex-span\"><i>A</i></span> lines containing <span class=\"tex-span\"><i>B</i></span> symbols each, describing the actual picture. The lines only contain uppercase English letters.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line print the number of possible good puzzles (in other words, the number of pairs <span class=\"tex-span\">(<i>X</i>, <i>Y</i>)</span> such that the puzzle with the corresponding element sizes will be good). This number should always be positive, because the whole picture is a good puzzle itself. </p><p>In the second line print two numbers — the sizes <span class=\"tex-span\"><i>X</i></span> and <span class=\"tex-span\"><i>Y</i></span> of the smallest possible element among all good puzzles. The comparison is made firstly by the area <span class=\"tex-span\"><i>XY</i></span> of one element and secondly — by the length <span class=\"tex-span\"><i>X</i></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 4<br />ABDC<br />ABDC<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br />2 1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 6<br />ABCCBA<br />ABCCBA<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br />2 6<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>The picture in the first sample test has the following good puzzles: <span class=\"tex-span\">(2, 1)</span>, <span class=\"tex-span\">(2, 2)</span>, <span class=\"tex-span\">(2, 4)</span>.</p></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='9473e10add7088b4f8e4b8826329f140'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/e-maxx\">e-maxx</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/e-maxx\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/e-maxx\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/e-maxx\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/e-maxx\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/e-maxx\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/e-maxx\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/e-maxx\" style=\"text-decoration:none;color:black !important;\">e-maxx's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1085\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1085\"> Codeforces Beta Round #50: Editorial for problem E\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/e-maxx\" title=\"International Master e-maxx\" class=\"rated-user user-orange\">e-maxx</a>,\r\n <span class=\"format-humantime\" title=\"Jan/11/2011 14:06\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><img src=\"/predownloaded/60/74/6074907f7dc69a9479975e89f95f7a1008e34a3d.png\" style=\"float: right;max-width: 100.0%;max-height: 100.0%;\" /></p><p><br /></p><p>The most important step on the way to solve this problem - is to understand that it's enough to consider only such rotations of the polygon, that one of its sides lies on the side of the room.<br /><br />Let's try to understand this fact. Suppose that the fact is wrong, and there exists such a position of vacuum cleaner, that neither of its sides lies on the side of the room. Denote as <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> the numbers of vertices that lie on the room sides. It's easy to understand that the polygon form between vertices <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> doesn't make any sense itself: for each rotation we can see that from the area of triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> some constant area is subtracted, while the concrete value of this constant depends on the polygon form.<br /><br />That's why we see that the polygon form doesn't influence on anything (if we have fixed numbers <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>), and we have just to minimize the area of right-angled triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>. But, taking into account that its hypotenuse is a constant, it's easy to see that the minimum is reached in borderline cases: i.e. when one of the polygon sides lies on the room side.<br /><br />So, we've proved the fact. Then we have to invent fast enough solution. We have already obtained an <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> solution: iterate over all sides of the polygon (i.e. iterating over all possible <span class=\"tex-span\"><i>i</i></span>), mentally push it to one side of the room, then find the threshold point <span class=\"tex-span\"><i>j</i></span>, then calculate answer for given <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>. Let's learn how to do these both things in <span class=\"tex-span\"><i>O</i>(1)</span>.<br /><br />In order to do the first thing (finding <span class=\"tex-span\"><i>j</i></span>) we can use a method of moving pointer: if we iterate over <span class=\"tex-span\"><i>i</i></span> in the same order as in the input file, then we can just maintain the right value of <span class=\"tex-span\"><i>j</i></span> (i.e. when we move from <span class=\"tex-span\"><i>i</i></span> to <span class=\"tex-span\"><i>i</i> + 1</span> we have to increase <span class=\"tex-span\"><i>j</i></span> several times, while it is getting further and further).<br /><br />In order to do the second thing (the area calculation) we have to do some precalculation. For example, we can find the mass center <span class=\"tex-span\"><i>Q</i></span> of the vacuum cleaner, and pre-calculate all partial sums <span class=\"tex-span\"><i>S</i>[<i>i</i>]</span> - sums of all triangles <span class=\"tex-span\"><i>QP</i>[<i>j</i> - 1]<i>P</i>[<i>j</i>]</span> for all <span class=\"tex-span\"><i>j</i> ≤ <i>i</i></span>. After this precalculation we can get the answer for every <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in <span class=\"tex-span\"><i>O</i>(1)</span> as a combination of difference of two values from <span class=\"tex-span\"><i>S</i>[]</span> and two triangles' areas: <span class=\"tex-span\"><i>QP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> and <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>.<br /><br /></p></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/54\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 50</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-123-1085\").click(function() {\n 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First Digit Law"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. First Digit Law</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>In the probability theory the following paradox called Benford's law is known: \"In many lists of random numbers taken from real sources, numbers starting with digit 1 occur much more often than numbers starting with any other digit\" (that's the simplest form of the law).</p><p>Having read about it on Codeforces, the Hedgehog got intrigued by the statement and wishes to thoroughly explore it. He finds the following similar problem interesting in particular: there are <span class=\"tex-span\"><i>N</i></span> random variables, the <span class=\"tex-span\"><i>i</i></span>-th of which can take any integer value from some segment <span class=\"tex-span\">[<i>L</i><sub class=\"lower-index\"><i>i</i></sub>;<i>R</i><sub class=\"lower-index\"><i>i</i></sub>]</span> (all numbers from this segment are equiprobable). It means that the value of the <span class=\"tex-span\"><i>i</i></span>-th quantity can be equal to any integer number from a given interval <span class=\"tex-span\">[<i>L</i><sub class=\"lower-index\"><i>i</i></sub>;<i>R</i><sub class=\"lower-index\"><i>i</i></sub>]</span> with probability <span class=\"tex-span\">1 / (<i>R</i><sub class=\"lower-index\"><i>i</i></sub> - <i>L</i><sub class=\"lower-index\"><i>i</i></sub> + 1)</span>.</p><p>The Hedgehog wants to know the probability of the event that the first digits of at least <span class=\"tex-span\"><i>K</i>%</span> of those values will be equal to one. In other words, let us consider some set of fixed values of these random variables and leave only the first digit (the MSD — most significant digit) of each value. Then let's count how many times the digit 1 is encountered and if it is encountered in at least <span class=\"tex-span\"><i>K</i></span> per cent of those <span class=\"tex-span\"><i>N</i></span> values, than such set of values will be called a good one. You have to find the probability that a set of values of the given random variables will be a good one.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains number <span class=\"tex-span\"><i>N</i></span> which is the number of random variables (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 1000</span>). Then follow <span class=\"tex-span\"><i>N</i></span> lines containing pairs of numbers <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\"><i>i</i></sub>, <i>R</i><sub class=\"lower-index\"><i>i</i></sub></span>, each of whom is a description of a random variable. It is guaranteed that <span class=\"tex-span\">1 ≤ <i>L</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>R</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">18</sup></span>.</p><p>The last line contains an integer <span class=\"tex-span\"><i>K</i></span> (<span class=\"tex-span\">0 ≤ <i>K</i> ≤ 100</span>).</p><p>All the numbers in the input file are integers.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the required probability. Print the fractional number with such a precision that the relative or absolute error of the result won't exceed <span class=\"tex-span\">10<sup class=\"upper-index\"> - 9</sup></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>1 2<br/>50<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.500000000000000</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/>1 2<br/>9 11<br/>50<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.833333333333333</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"31a268e3fcff676b39e54d2c3c5655ad\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"d5d8da0ccc5d8f6f652c562154ed763cebdcc2c5\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/54\">Codeforces Beta Round 50</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='31a268e3fcff676b39e54d2c3c5655ad'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/54/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Probabilities, expected values, statistics, random variables, etc\">\r\n probabilities\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2000\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='31a268e3fcff676b39e54d2c3c5655ad'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"284\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='31a268e3fcff676b39e54d2c3c5655ad'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"284\"/>\r\n <input name=\"tagName\" 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0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1083\" title=\"Codeforces Beta Round #50\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"193:194\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1085\" title=\"Codeforces Beta Round #50: Editorial for problem E\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"805:806\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1087\" title=\"Codeforces Beta Round #50: Разбор задачи D\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"807:808\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1088\" title=\"Codeforces Beta Round #50: Editorial for problem C\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"809:810\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/54\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/54/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/54/my\">My Submissions</a></li>\r\n <li><a\r\n 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result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_1e3a108a69467330a621a8174ba3fc0d7dec5e43\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. First Digit Law</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>In the probability theory the following paradox called Benford's law is known: "In many lists of random numbers taken from real sources, numbers starting with digit 1 occur much more often than numbers starting with any other digit" (that's the simplest form of the law).</p><p>Having read about it on Codeforces, the Hedgehog got intrigued by the statement and wishes to thoroughly explore it. He finds the following similar problem interesting in particular: there are <span class=\"tex-span\"><i>N</i></span> random variables, the <span class=\"tex-span\"><i>i</i></span>-th of which can take any integer value from some segment <span class=\"tex-span\">[<i>L</i><sub class=\"lower-index\"><i>i</i></sub>;<i>R</i><sub class=\"lower-index\"><i>i</i></sub>]</span> (all numbers from this segment are equiprobable). It means that the value of the <span class=\"tex-span\"><i>i</i></span>-th quantity can be equal to any integer number from a given interval <span class=\"tex-span\">[<i>L</i><sub class=\"lower-index\"><i>i</i></sub>;<i>R</i><sub class=\"lower-index\"><i>i</i></sub>]</span> with probability <span class=\"tex-span\">1 / (<i>R</i><sub class=\"lower-index\"><i>i</i></sub> - <i>L</i><sub class=\"lower-index\"><i>i</i></sub> + 1)</span>.</p><p>The Hedgehog wants to know the probability of the event that the first digits of at least <span class=\"tex-span\"><i>K</i>%</span> of those values will be equal to one. In other words, let us consider some set of fixed values of these random variables and leave only the first digit (the MSD — most significant digit) of each value. Then let's count how many times the digit 1 is encountered and if it is encountered in at least <span class=\"tex-span\"><i>K</i></span> per cent of those <span class=\"tex-span\"><i>N</i></span> values, than such set of values will be called a good one. You have to find the probability that a set of values of the given random variables will be a good one.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains number <span class=\"tex-span\"><i>N</i></span> which is the number of random variables (<span class=\"tex-span\">1 ≤ <i>N</i> ≤ 1000</span>). Then follow <span class=\"tex-span\"><i>N</i></span> lines containing pairs of numbers <span class=\"tex-span\"><i>L</i><sub class=\"lower-index\"><i>i</i></sub>, <i>R</i><sub class=\"lower-index\"><i>i</i></sub></span>, each of whom is a description of a random variable. It is guaranteed that <span class=\"tex-span\">1 ≤ <i>L</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>R</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">18</sup></span>.</p><p>The last line contains an integer <span class=\"tex-span\"><i>K</i></span> (<span class=\"tex-span\">0 ≤ <i>K</i> ≤ 100</span>).</p><p>All the numbers in the input file are integers.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the required probability. Print the fractional number with such a precision that the relative or absolute error of the result won't exceed <span class=\"tex-span\">10<sup class=\"upper-index\"> - 9</sup></span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />1 2<br />50<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.500000000000000</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2<br />1 2<br />9 11<br />50<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.833333333333333</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='9473e10add7088b4f8e4b8826329f140'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/e-maxx\">e-maxx</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/e-maxx\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/e-maxx\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/e-maxx\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/e-maxx\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/e-maxx\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/e-maxx\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/e-maxx\" style=\"text-decoration:none;color:black !important;\">e-maxx's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1085\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1085\"> Codeforces Beta Round #50: Editorial for problem E\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/e-maxx\" title=\"International Master e-maxx\" class=\"rated-user user-orange\">e-maxx</a>,\r\n <span class=\"format-humantime\" title=\"Jan/11/2011 14:06\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><img src=\"/predownloaded/60/74/6074907f7dc69a9479975e89f95f7a1008e34a3d.png\" style=\"float: right;max-width: 100.0%;max-height: 100.0%;\" /></p><p><br /></p><p>The most important step on the way to solve this problem - is to understand that it's enough to consider only such rotations of the polygon, that one of its sides lies on the side of the room.<br /><br />Let's try to understand this fact. Suppose that the fact is wrong, and there exists such a position of vacuum cleaner, that neither of its sides lies on the side of the room. Denote as <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> the numbers of vertices that lie on the room sides. It's easy to understand that the polygon form between vertices <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> doesn't make any sense itself: for each rotation we can see that from the area of triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> some constant area is subtracted, while the concrete value of this constant depends on the polygon form.<br /><br />That's why we see that the polygon form doesn't influence on anything (if we have fixed numbers <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>), and we have just to minimize the area of right-angled triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>. But, taking into account that its hypotenuse is a constant, it's easy to see that the minimum is reached in borderline cases: i.e. when one of the polygon sides lies on the room side.<br /><br />So, we've proved the fact. Then we have to invent fast enough solution. We have already obtained an <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> solution: iterate over all sides of the polygon (i.e. iterating over all possible <span class=\"tex-span\"><i>i</i></span>), mentally push it to one side of the room, then find the threshold point <span class=\"tex-span\"><i>j</i></span>, then calculate answer for given <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>. Let's learn how to do these both things in <span class=\"tex-span\"><i>O</i>(1)</span>.<br /><br />In order to do the first thing (finding <span class=\"tex-span\"><i>j</i></span>) we can use a method of moving pointer: if we iterate over <span class=\"tex-span\"><i>i</i></span> in the same order as in the input file, then we can just maintain the right value of <span class=\"tex-span\"><i>j</i></span> (i.e. when we move from <span class=\"tex-span\"><i>i</i></span> to <span class=\"tex-span\"><i>i</i> + 1</span> we have to increase <span class=\"tex-span\"><i>j</i></span> several times, while it is getting further and further).<br /><br />In order to do the second thing (the area calculation) we have to do some precalculation. For example, we can find the mass center <span class=\"tex-span\"><i>Q</i></span> of the vacuum cleaner, and pre-calculate all partial sums <span class=\"tex-span\"><i>S</i>[<i>i</i>]</span> - sums of all triangles <span class=\"tex-span\"><i>QP</i>[<i>j</i> - 1]<i>P</i>[<i>j</i>]</span> for all <span class=\"tex-span\"><i>j</i> ≤ <i>i</i></span>. After this precalculation we can get the answer for every <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in <span class=\"tex-span\"><i>O</i>(1)</span> as a combination of difference of two values from <span class=\"tex-span\"><i>S</i>[]</span> and two triangles' areas: <span class=\"tex-span\"><i>QP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> and <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>.<br /><br /></p></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/54\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 50</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-123-1085\").click(function() {\n 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Writing a Song"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Writing a Song</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>One of the Hedgehog and his friend's favorite entertainments is to take some sentence or a song and replace half of the words (sometimes even all of them) with each other's names.</p><p>The friend's birthday is approaching and the Hedgehog decided to make a special present to his friend: a very long song, where his name will be repeated many times. But try as he might, he can't write a decent song!</p><p>The problem is that the Hedgehog has already decided how long the resulting sentence should be (i.e. how many letters it should contain) and in which positions in the sentence the friend's name should occur, and it must not occur in any other position in the sentence. Besides, the Hedgehog decided to limit himself to using only the first <span class=\"tex-span\"><i>K</i></span> letters of an English alphabet in this sentence (so it will be not even a sentence, but one long word).</p><p>The resulting problem is indeed quite complicated, that's why the Hedgehog asks you to help him and write a program that will make the desired word by the given name <span class=\"tex-span\"><i>P</i></span>, the length <span class=\"tex-span\"><i>N</i></span> of the required word, the given positions of the occurrences of the name <span class=\"tex-span\"><i>P</i></span> in the desired word and the alphabet's size <span class=\"tex-span\"><i>K</i></span>. Note that the occurrences of the name can overlap with each other.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains numbers <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>K</i></span> which are the length of the required string and the alphabet size accordingly. The limitations are: <span class=\"tex-span\">1 ≤ <i>N</i> ≤ 100</span>, <span class=\"tex-span\">2 ≤ <i>K</i> ≤ 26</span>.</p><p>The second line contains the name <span class=\"tex-span\"><i>P</i></span> which is a non-empty string whose length does not exceed <span class=\"tex-span\"><i>N</i></span> characters. The string consists only of the first <span class=\"tex-span\"><i>K</i></span> lowercase symbols of an English alphabet.</p><p>The third line contains the string of length <span class=\"tex-span\"><i>N</i> - <i>length</i>(<i>P</i>) + 1</span>, consisting only of numbers zero and one. A number one in the <span class=\"tex-span\"><i>i</i></span>-th position means that an occurrence of the name <span class=\"tex-span\"><i>P</i></span> should start from <span class=\"tex-span\"><i>i</i></span>-th position of the desired word, while a zero means that there is no occurrence starting here. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the desired word <span class=\"tex-span\"><i>S</i></span>. If there are several answers, print any of them.</p><p>If there is no solution, then print \"No solution\".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 2<br/>aba<br/>101<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>ababa</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5 2<br/>a<br/>10001<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>abbba</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>6 2<br/>abba<br/>101<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>No solution</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"5a9dda9d1e65394753fab3986e15dccd\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"d5d8da0ccc5d8f6f652c562154ed763cebdcc2c5\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/54\">Codeforces Beta Round 50</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Brute force\">\r\n brute force\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Dynamic programming\">\r\n dp\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Prefix- and Z-functions, suffix structures, Knuth–Morris–Pratt algorithm, etc\">\r\n strings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n 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both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1085\" title=\"Codeforces Beta Round #50: Editorial for problem E\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"805:806\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1087\" title=\"Codeforces Beta Round #50: Разбор задачи D\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"807:808\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1088\" title=\"Codeforces Beta Round #50: Editorial for problem C\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"809:810\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/54\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/54/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/54/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/54/status\">Status</a></li>\r\n <li><a\r\n 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.pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_8a37c656332fb77d2ffe3e2e8e605bf6a41f78f7\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Writing a Song</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>One of the Hedgehog and his friend's favorite entertainments is to take some sentence or a song and replace half of the words (sometimes even all of them) with each other's names.</p><p>The friend's birthday is approaching and the Hedgehog decided to make a special present to his friend: a very long song, where his name will be repeated many times. But try as he might, he can't write a decent song!</p><p>The problem is that the Hedgehog has already decided how long the resulting sentence should be (i.e. how many letters it should contain) and in which positions in the sentence the friend's name should occur, and it must not occur in any other position in the sentence. Besides, the Hedgehog decided to limit himself to using only the first <span class=\"tex-span\"><i>K</i></span> letters of an English alphabet in this sentence (so it will be not even a sentence, but one long word).</p><p>The resulting problem is indeed quite complicated, that's why the Hedgehog asks you to help him and write a program that will make the desired word by the given name <span class=\"tex-span\"><i>P</i></span>, the length <span class=\"tex-span\"><i>N</i></span> of the required word, the given positions of the occurrences of the name <span class=\"tex-span\"><i>P</i></span> in the desired word and the alphabet's size <span class=\"tex-span\"><i>K</i></span>. Note that the occurrences of the name can overlap with each other.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains numbers <span class=\"tex-span\"><i>N</i></span> and <span class=\"tex-span\"><i>K</i></span> which are the length of the required string and the alphabet size accordingly. The limitations are: <span class=\"tex-span\">1 ≤ <i>N</i> ≤ 100</span>, <span class=\"tex-span\">2 ≤ <i>K</i> ≤ 26</span>.</p><p>The second line contains the name <span class=\"tex-span\"><i>P</i></span> which is a non-empty string whose length does not exceed <span class=\"tex-span\"><i>N</i></span> characters. The string consists only of the first <span class=\"tex-span\"><i>K</i></span> lowercase symbols of an English alphabet.</p><p>The third line contains the string of length <span class=\"tex-span\"><i>N</i> - <i>length</i>(<i>P</i>) + 1</span>, consisting only of numbers zero and one. A number one in the <span class=\"tex-span\"><i>i</i></span>-th position means that an occurrence of the name <span class=\"tex-span\"><i>P</i></span> should start from <span class=\"tex-span\"><i>i</i></span>-th position of the desired word, while a zero means that there is no occurrence starting here. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the desired word <span class=\"tex-span\"><i>S</i></span>. If there are several answers, print any of them.</p><p>If there is no solution, then print "No solution".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 2<br />aba<br />101<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>ababa</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5 2<br />a<br />10001<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>abbba</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>6 2<br />abba<br />101<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>No solution</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='9473e10add7088b4f8e4b8826329f140'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n </label>\r\n </div>\r\n <div style=\"padding: 0 1em 1em 1em;text-align:right;\">\r\n <input style=\"height:1.65em;padding:0 0.75em;\" type=\"submit\" value=\"Find\"/>\r\n </div>\r\n </form>\r\n </div>\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".handleBox\").autocomplete(\"/data/handles\", {\r\n delay: 200,\r\n width: 200,\r\n selectFirst: false,\r\n matchContains: true,\r\n minChars: 3\r\n });\r\n $(\".handleForm\").attr(\"autocomplete\", \"off\").submit(function () {\r\n var link = \"/profile/userHandle\".replace(\r\n \"userHandle\", $(this).find(\".handleBox\").val()\r\n );\r\n window.location = link;\r\n return false;\r\n });\r\n });\n </script>\n\r\n\r\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Recent actions\n <div class=\"top-links\">\n </div>\n </div>\n <div class=\"recent-actions\">\r\n <ul>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/yeon_gist\" title=\"Newbie yeon_gist\" class=\"rated-user user-gray\">yeon_gist</a> →\r\n <a href=\"/blog/entry/121170\">plusMinusPermutation computing error</a>\r\n <img alt=\"Text created or updated\" title=\"Text created or updated\" src=\"//codeforces.org/s/81027/images/icons/x-update-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/altforminuscontribution\" title=\"Newbie altforminuscontribution\" class=\"rated-user user-gray\">altforminuscontribution</a> →\r\n <a href=\"/blog/entry/121162\">My screen get unexpectedly big, what should I do</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/atcoder_official\" title=\"Unrated, atcoder_official\" class=\"rated-user user-black\">atcoder_official</a> →\r\n <a href=\"/blog/entry/121120\">We will hold UNIQUE VISION Programming Contest 2023 Autumn(AtCoder Beginner Contest 323)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/YouStill_DontKnowMeYet\" title=\"Candidate Master YouStill_DontKnowMeYet\" class=\"rated-user user-violet\">YouStill_DontKnowMeYet</a> →\r\n <a href=\"/blog/entry/117659\">[GYM] Al-Baath Collegiate Programming Contest 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/ankancool\" title=\"Expert ankancool\" class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/dino_merlin\" title=\"Expert dino_merlin\" class=\"rated-user user-blue\">dino_merlin</a> →\r\n <a href=\"/blog/entry/121145\">Intuitive approach for CEOI Kangaroo?</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/icecuber\" title=\"Grandmaster icecuber\" class=\"rated-user user-red\">icecuber</a> →\r\n <a href=\"/blog/entry/70018\">CSES DP section editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/e-maxx\">e-maxx</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/e-maxx\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/e-maxx\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/e-maxx\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/e-maxx\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/e-maxx\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/e-maxx\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/e-maxx\" style=\"text-decoration:none;color:black !important;\">e-maxx's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1085\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1085\"> Codeforces Beta Round #50: Editorial for problem E\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/e-maxx\" title=\"International Master e-maxx\" class=\"rated-user user-orange\">e-maxx</a>,\r\n <span class=\"format-humantime\" title=\"Jan/11/2011 14:06\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><img src=\"/predownloaded/60/74/6074907f7dc69a9479975e89f95f7a1008e34a3d.png\" style=\"float: right;max-width: 100.0%;max-height: 100.0%;\" /></p><p><br /></p><p>The most important step on the way to solve this problem - is to understand that it's enough to consider only such rotations of the polygon, that one of its sides lies on the side of the room.<br /><br />Let's try to understand this fact. Suppose that the fact is wrong, and there exists such a position of vacuum cleaner, that neither of its sides lies on the side of the room. Denote as <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> the numbers of vertices that lie on the room sides. It's easy to understand that the polygon form between vertices <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> doesn't make any sense itself: for each rotation we can see that from the area of triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> some constant area is subtracted, while the concrete value of this constant depends on the polygon form.<br /><br />That's why we see that the polygon form doesn't influence on anything (if we have fixed numbers <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>), and we have just to minimize the area of right-angled triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>. But, taking into account that its hypotenuse is a constant, it's easy to see that the minimum is reached in borderline cases: i.e. when one of the polygon sides lies on the room side.<br /><br />So, we've proved the fact. Then we have to invent fast enough solution. We have already obtained an <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> solution: iterate over all sides of the polygon (i.e. iterating over all possible <span class=\"tex-span\"><i>i</i></span>), mentally push it to one side of the room, then find the threshold point <span class=\"tex-span\"><i>j</i></span>, then calculate answer for given <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>. Let's learn how to do these both things in <span class=\"tex-span\"><i>O</i>(1)</span>.<br /><br />In order to do the first thing (finding <span class=\"tex-span\"><i>j</i></span>) we can use a method of moving pointer: if we iterate over <span class=\"tex-span\"><i>i</i></span> in the same order as in the input file, then we can just maintain the right value of <span class=\"tex-span\"><i>j</i></span> (i.e. when we move from <span class=\"tex-span\"><i>i</i></span> to <span class=\"tex-span\"><i>i</i> + 1</span> we have to increase <span class=\"tex-span\"><i>j</i></span> several times, while it is getting further and further).<br /><br />In order to do the second thing (the area calculation) we have to do some precalculation. For example, we can find the mass center <span class=\"tex-span\"><i>Q</i></span> of the vacuum cleaner, and pre-calculate all partial sums <span class=\"tex-span\"><i>S</i>[<i>i</i>]</span> - sums of all triangles <span class=\"tex-span\"><i>QP</i>[<i>j</i> - 1]<i>P</i>[<i>j</i>]</span> for all <span class=\"tex-span\"><i>j</i> ≤ <i>i</i></span>. After this precalculation we can get the answer for every <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in <span class=\"tex-span\"><i>O</i>(1)</span> as a combination of difference of two values from <span class=\"tex-span\"><i>S</i>[]</span> and two triangles' areas: <span class=\"tex-span\"><i>QP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> and <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>.<br /><br /></p></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/54\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 50</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-123-1085\").click(function() {\n 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Vacuum Сleaner"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Vacuum Сleaner</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>One winter evening the Hedgehog was relaxing at home in his cozy armchair and clicking through the TV channels. Stumbled on an issue of «TopShop», the Hedgehog was about to change the channel when all of a sudden he was stopped by an advertisement of a new wondrous invention.</p><p>Actually, a vacuum cleaner was advertised there. It was called Marvellous Vacuum and it doesn't even need a human to operate it while it cleans! The vacuum cleaner can move around the flat on its own: it moves in some direction and if it hits an obstacle there, it automatically chooses a new direction. Sooner or later this vacuum cleaner will travel through all the room and clean it all. Having remembered how much time the Hedgehog spends every time on cleaning (surely, no less than a half of the day), he got eager to buy this wonder.</p><p>However, the Hedgehog quickly understood that the cleaner has at least one weak point: it won't clean well in the room's corners because it often won't able to reach the corner due to its shape. To estimate how serious is this drawback in practice, the Hedgehog asked you to write for him the corresponding program.</p><p>You will be given the cleaner's shape in the top view. We will consider only the cases when the vacuum cleaner is represented as a convex polygon. The room is some infinitely large rectangle. We consider one corner of this room and want to find such a rotation of the vacuum cleaner so that it, being pushed into this corner, will leave the minimum possible area in the corner uncovered.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>N</i></span> which represents the number of vertices of the vacuum cleaner's polygon (<span class=\"tex-span\">3 ≤ <i>N</i> ≤ 4·10<sup class=\"upper-index\">4</sup></span>). Then follow <span class=\"tex-span\"><i>N</i></span> lines each containing two numbers — the coordinates of a vertex of the polygon. All the coordinates are integer and their absolute values do not exceed <span class=\"tex-span\">10<sup class=\"upper-index\">6</sup></span>.</p><p>It is guaranteed that the given polygon is nondegenerate and convex (no three points lie on the same line). The polygon vertices are given in a clockwise or counter-clockwise direction.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the minimum possible uncovered area. The answer will be accepted if it is within <span class=\"tex-span\">10<sup class=\"upper-index\"> - 6</sup></span> of absolute or relative error from the correct answer.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>0 0<br/>1 0<br/>1 1<br/>0 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.00000000000000000000</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>8<br/>1 2<br/>2 1<br/>2 -1<br/>1 -2<br/>-1 -2<br/>-2 -1<br/>-2 1<br/>-1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.50000000000000000000</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"b8e8a00bb82a9e6ff6d95593fad29a48\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"d5d8da0ccc5d8f6f652c562154ed763cebdcc2c5\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Geometry, computational geometry\">\r\n geometry\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2700\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='b8e8a00bb82a9e6ff6d95593fad29a48'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"286\"/>\r\n <input name=\"tagName\" 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href=\"/blog/entry/1083\" title=\"Codeforces Beta Round #50\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"193:194\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1085\" title=\"Codeforces Beta Round #50: Editorial for problem E\" target=\"_blank\">Tutorial #1</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"805:806\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1087\" title=\"Codeforces Beta Round #50: Разбор задачи D\" target=\"_blank\">Tutorial #2</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"807:808\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1088\" title=\"Codeforces Beta Round #50: Editorial for problem C\" target=\"_blank\">Tutorial #3</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"809:810\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/54\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/54/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/54/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/54/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/54/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/54/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/54/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/54/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: 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node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_d4a20897a96fc627399883cb8f96c22b665b4b48\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Vacuum Сleaner</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>One winter evening the Hedgehog was relaxing at home in his cozy armchair and clicking through the TV channels. Stumbled on an issue of «TopShop», the Hedgehog was about to change the channel when all of a sudden he was stopped by an advertisement of a new wondrous invention.</p><p>Actually, a vacuum cleaner was advertised there. It was called Marvellous Vacuum and it doesn't even need a human to operate it while it cleans! The vacuum cleaner can move around the flat on its own: it moves in some direction and if it hits an obstacle there, it automatically chooses a new direction. Sooner or later this vacuum cleaner will travel through all the room and clean it all. Having remembered how much time the Hedgehog spends every time on cleaning (surely, no less than a half of the day), he got eager to buy this wonder.</p><p>However, the Hedgehog quickly understood that the cleaner has at least one weak point: it won't clean well in the room's corners because it often won't able to reach the corner due to its shape. To estimate how serious is this drawback in practice, the Hedgehog asked you to write for him the corresponding program.</p><p>You will be given the cleaner's shape in the top view. We will consider only the cases when the vacuum cleaner is represented as a convex polygon. The room is some infinitely large rectangle. We consider one corner of this room and want to find such a rotation of the vacuum cleaner so that it, being pushed into this corner, will leave the minimum possible area in the corner uncovered.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>N</i></span> which represents the number of vertices of the vacuum cleaner's polygon (<span class=\"tex-span\">3 ≤ <i>N</i> ≤ 4·10<sup class=\"upper-index\">4</sup></span>). Then follow <span class=\"tex-span\"><i>N</i></span> lines each containing two numbers — the coordinates of a vertex of the polygon. All the coordinates are integer and their absolute values do not exceed <span class=\"tex-span\">10<sup class=\"upper-index\">6</sup></span>.</p><p>It is guaranteed that the given polygon is nondegenerate and convex (no three points lie on the same line). The polygon vertices are given in a clockwise or counter-clockwise direction.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print the minimum possible uncovered area. The answer will be accepted if it is within <span class=\"tex-span\">10<sup class=\"upper-index\"> - 6</sup></span> of absolute or relative error from the correct answer.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />0 0<br />1 0<br />1 1<br />0 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.00000000000000000000</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>8<br />1 2<br />2 1<br />2 -1<br />1 -2<br />-1 -2<br />-2 -1<br />-2 1<br />-1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.50000000000000000000</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:51</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='9473e10add7088b4f8e4b8826329f140'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/e-maxx\">e-maxx</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/e-maxx\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/e-maxx\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/e-maxx\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/e-maxx\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/e-maxx\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/e-maxx\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/e-maxx\" style=\"text-decoration:none;color:black !important;\">e-maxx's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1085\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1085\"> Codeforces Beta Round #50: Editorial for problem E\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/e-maxx\" title=\"International Master e-maxx\" class=\"rated-user user-orange\">e-maxx</a>,\r\n <span class=\"format-humantime\" title=\"Jan/11/2011 14:06\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><p><img src=\"/predownloaded/60/74/6074907f7dc69a9479975e89f95f7a1008e34a3d.png\" style=\"float: right;max-width: 100.0%;max-height: 100.0%;\" /></p><p><br /></p><p>The most important step on the way to solve this problem - is to understand that it's enough to consider only such rotations of the polygon, that one of its sides lies on the side of the room.<br /><br />Let's try to understand this fact. Suppose that the fact is wrong, and there exists such a position of vacuum cleaner, that neither of its sides lies on the side of the room. Denote as <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> the numbers of vertices that lie on the room sides. It's easy to understand that the polygon form between vertices <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> doesn't make any sense itself: for each rotation we can see that from the area of triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> some constant area is subtracted, while the concrete value of this constant depends on the polygon form.<br /><br />That's why we see that the polygon form doesn't influence on anything (if we have fixed numbers <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>), and we have just to minimize the area of right-angled triangle <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>. But, taking into account that its hypotenuse is a constant, it's easy to see that the minimum is reached in borderline cases: i.e. when one of the polygon sides lies on the room side.<br /><br />So, we've proved the fact. Then we have to invent fast enough solution. We have already obtained an <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span> solution: iterate over all sides of the polygon (i.e. iterating over all possible <span class=\"tex-span\"><i>i</i></span>), mentally push it to one side of the room, then find the threshold point <span class=\"tex-span\"><i>j</i></span>, then calculate answer for given <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span>. Let's learn how to do these both things in <span class=\"tex-span\"><i>O</i>(1)</span>.<br /><br />In order to do the first thing (finding <span class=\"tex-span\"><i>j</i></span>) we can use a method of moving pointer: if we iterate over <span class=\"tex-span\"><i>i</i></span> in the same order as in the input file, then we can just maintain the right value of <span class=\"tex-span\"><i>j</i></span> (i.e. when we move from <span class=\"tex-span\"><i>i</i></span> to <span class=\"tex-span\"><i>i</i> + 1</span> we have to increase <span class=\"tex-span\"><i>j</i></span> several times, while it is getting further and further).<br /><br />In order to do the second thing (the area calculation) we have to do some precalculation. For example, we can find the mass center <span class=\"tex-span\"><i>Q</i></span> of the vacuum cleaner, and pre-calculate all partial sums <span class=\"tex-span\"><i>S</i>[<i>i</i>]</span> - sums of all triangles <span class=\"tex-span\"><i>QP</i>[<i>j</i> - 1]<i>P</i>[<i>j</i>]</span> for all <span class=\"tex-span\"><i>j</i> ≤ <i>i</i></span>. After this precalculation we can get the answer for every <span class=\"tex-span\"><i>i</i></span> and <span class=\"tex-span\"><i>j</i></span> in <span class=\"tex-span\"><i>O</i>(1)</span> as a combination of difference of two values from <span class=\"tex-span\"><i>S</i>[]</span> and two triangles' areas: <span class=\"tex-span\"><i>QP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span> and <span class=\"tex-span\"><i>OP</i>[<i>i</i>]<i>P</i>[<i>j</i>]</span>.<br /><br /></p></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/54\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 50</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-123-1085\").click(function() {\n 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Flea travel"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Flea travel</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>A flea is sitting at one of the <span class=\"tex-span\"><i>n</i></span> hassocks, arranged in a circle, at the moment. After minute number <span class=\"tex-span\"><i>k</i></span> the flea jumps through <span class=\"tex-span\"><i>k</i> - 1</span> hassoсks (clockwise). For example, after the first minute the flea jumps to the neighboring hassock. You should answer: will the flea visit all the hassocks or not. We assume that flea has infinitely much time for this jumping.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The only line contains single integer: <span class=\"tex-span\">1 ≤ <i>n</i> ≤ 1000</span> — number of hassocks.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output \"<span class=\"tex-font-style-tt\">YES</span>\" if all the hassocks will be visited and \"<span class=\"tex-font-style-tt\">NO</span>\" otherwise.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"d3bc5cf8f0ef16034f7e7b357836180b\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"af37ad906831b23242765479fa0e0da4f3a2b149\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='d3bc5cf8f0ef16034f7e7b357836180b'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/55/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Mathematics including integration, differential equations, etc\">\r\n math\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1200\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='d3bc5cf8f0ef16034f7e7b357836180b'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"287\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='d3bc5cf8f0ef16034f7e7b357836180b'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"287\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1107\" title=\"Codeforces Beta Round #51\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"195:196\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1109\" title=\"Round 51, D\" target=\"_blank\">Round 51, D</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"197:198\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1113\" title=\"Round 51, E\" target=\"_blank\">Round 51, E</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"205:206\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1112\" title=\"Round 51, C\" target=\"_blank\">Round 51, C</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"203:204\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1111\" title=\"Round 51, B\" target=\"_blank\">Round 51, B</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"201:202\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1110\" title=\"Round 51, A\" target=\"_blank\">Round 51, A</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"199:200\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/55\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/55/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/55/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/55/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/55/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/55/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/55/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/55/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || 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}\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_b40742d03489d86f488ac92bf525c925d976f19f\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Flea travel</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>A flea is sitting at one of the <span class=\"tex-span\"><i>n</i></span> hassocks, arranged in a circle, at the moment. After minute number <span class=\"tex-span\"><i>k</i></span> the flea jumps through <span class=\"tex-span\"><i>k</i> - 1</span> hassoсks (clockwise). For example, after the first minute the flea jumps to the neighboring hassock. You should answer: will the flea visit all the hassocks or not. We assume that flea has infinitely much time for this jumping.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The only line contains single integer: <span class=\"tex-span\">1 ≤ <i>n</i> ≤ 1000</span> — number of hassocks.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output "<span class=\"tex-font-style-tt\">YES</span>" if all the hassocks will be visited and "<span class=\"tex-font-style-tt\">NO</span>" otherwise.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n 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etc\"]"},"short_tags":{"kind":"string","value":"[\"implementation\", \"math\", \"*1200\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":285,"cells":{"problem_id":{"kind":"string","value":"55B"},"contest":{"kind":"string","value":"55"},"problem":{"kind":"string","value":"B"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"B. Smallest number"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Smallest number</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Recently, Vladimir got bad mark in algebra again. To avoid such unpleasant events in future he decided to train his arithmetic skills. He wrote four integer numbers <span class=\"tex-span\"><i>a</i></span>, <span class=\"tex-span\"><i>b</i></span>, <span class=\"tex-span\"><i>c</i></span>, <span class=\"tex-span\"><i>d</i></span> on the blackboard. During each of the next three minutes he took two numbers from the blackboard (not necessarily adjacent) and replaced them with their sum or their product. In the end he got one number. Unfortunately, due to the awful memory he forgot that number, but he remembers four original numbers, sequence of the operations and his surprise because of the very small result. Help Vladimir remember the forgotten number: find the smallest number that can be obtained from the original numbers by the given sequence of operations.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>First line contains four integers separated by space: <span class=\"tex-span\">0 ≤ <i>a</i>, <i>b</i>, <i>c</i>, <i>d</i> ≤ 1000</span> — the original numbers. Second line contains three signs ('+' or '*' each) separated by space — the sequence of the operations in the order of performing. ('+' stands for addition, '*' — multiplication)</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output one integer number — the minimal result which can be obtained.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1 1 1 1<br/>+ + *<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 2 2<br/>* * +<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 2 3 4<br/>* + +<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"21bc3e1a7a1e8d5bda74fb2d94788388\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"af37ad906831b23242765479fa0e0da4f3a2b149\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/55\">Codeforces Beta Round 51</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='21bc3e1a7a1e8d5bda74fb2d94788388'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/55/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Brute force\">\r\n brute force\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='21bc3e1a7a1e8d5bda74fb2d94788388'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"288\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='21bc3e1a7a1e8d5bda74fb2d94788388'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"288\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1107\" title=\"Codeforces Beta Round #51\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"195:196\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1109\" title=\"Round 51, D\" target=\"_blank\">Round 51, D</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"197:198\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1113\" title=\"Round 51, E\" target=\"_blank\">Round 51, E</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"205:206\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1112\" title=\"Round 51, C\" target=\"_blank\">Round 51, C</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"203:204\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1111\" title=\"Round 51, B\" target=\"_blank\">Round 51, B</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"201:202\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1110\" title=\"Round 51, A\" target=\"_blank\">Round 51, A</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"199:200\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/55\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/55/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/55/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/55/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/55/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/55/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/55/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/55/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_357592f62fcbdfc94613d4a09949feecaa5c97f0\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Smallest number</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Recently, Vladimir got bad mark in algebra again. To avoid such unpleasant events in future he decided to train his arithmetic skills. He wrote four integer numbers <span class=\"tex-span\"><i>a</i></span>, <span class=\"tex-span\"><i>b</i></span>, <span class=\"tex-span\"><i>c</i></span>, <span class=\"tex-span\"><i>d</i></span> on the blackboard. During each of the next three minutes he took two numbers from the blackboard (not necessarily adjacent) and replaced them with their sum or their product. In the end he got one number. Unfortunately, due to the awful memory he forgot that number, but he remembers four original numbers, sequence of the operations and his surprise because of the very small result. Help Vladimir remember the forgotten number: find the smallest number that can be obtained from the original numbers by the given sequence of operations.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>First line contains four integers separated by space: <span class=\"tex-span\">0 ≤ <i>a</i>, <i>b</i>, <i>c</i>, <i>d</i> ≤ 1000</span> — the original numbers. Second line contains three signs ('+' or '*' each) separated by space — the sequence of the operations in the order of performing. ('+' stands for addition, '*' — multiplication)</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output one integer number — the minimal result which can be obtained.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1 1 1 1<br />+ + *<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 2 2<br />* * +<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>8<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1 2 3 4<br />* + +<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = 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\"*1600\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":286,"cells":{"problem_id":{"kind":"string","value":"55C"},"contest":{"kind":"string","value":"55"},"problem":{"kind":"string","value":"C"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"C. Pie or die"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Pie or die</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Volodya and Vlad play the following game. There are <span class=\"tex-span\"><i>k</i></span> pies at the cells of <span class=\"tex-span\"><i>n</i> × <i>m</i></span> board. Each turn Volodya moves one pie to the neighbouring (by side) cell. If the pie lies at the border of the board then Volodya can move it outside the board, get the pie and win. After Volodya's move, Vlad bans some edge at the border of the board of length 1 (between two knots of the board) so that Volodya is not able to move the pie outside the board through this edge anymore. The question is: will Volodya win this game? We suppose both players follow the optimal strategy.</p><center><img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/1878febc6260322dfe8bbc217a4ebbafa22eb482.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/></center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>First line contains 3 integers, separated by space: <span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 100</span> — dimensions of the board and <span class=\"tex-span\">0 ≤ <i>k</i> ≤ 100</span> — the number of pies. Each of the next <span class=\"tex-span\"><i>k</i></span> lines contains 2 integers, separated by space: <span class=\"tex-span\">1 ≤ <i>x</i> ≤ <i>n</i></span>, <span class=\"tex-span\">1 ≤ <i>y</i> ≤ <i>m</i></span> — coordinates of the corresponding pie. There could be more than one pie at a cell. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output only one word: \"<span class=\"tex-font-style-tt\">YES</span>\" — if Volodya wins, \"<span class=\"tex-font-style-tt\">NO</span>\" — otherwise.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 1<br/>1 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 4 0<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>100 50 2<br/>50 25<br/>50 25<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO</pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"63dd214b3e5bea5ef119b79caa0ceea1\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"af37ad906831b23242765479fa0e0da4f3a2b149\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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$(\"a[rel='photobox']\").colorbox();\n\n\n function showAnnouncements(json) {\n //info(\"j=\" + JSON.stringify(json));\n\n if (json.t != \"a\") {\n return;\n }\n\n setTimeout(function() {\n Codeforces.showAnnouncements(json.d, \"en\");\n }, Math.random() * 500);\n }\n\n function showEventCatcherUserMessage(json) {\n if (json.t == \"s\") {\n var points = json.d[5];\n var passedTestCount = json.d[7];\n var judgedTestCount = json.d[8];\n var verdict = preparedVerdictFormats[json.d[12]];\n var verdictPrototypeDiv = $(\".verdictPrototypeDiv\");\n verdictPrototypeDiv.html(verdict);\n if (judgedTestCount != null && judgedTestCount != undefined) {\n verdictPrototypeDiv.find(\".verdict-format-judged\").text(judgedTestCount);\n }\n if (passedTestCount != null && passedTestCount != undefined) {\n verdictPrototypeDiv.find(\".verdict-format-passed\").text(passedTestCount);\n }\n if (points != null && points != undefined) {\n verdictPrototypeDiv.find(\".verdict-format-points\").text(points);\n }\n Codeforces.showMessage(verdictPrototypeDiv.text());\n }\n }\n\n $(\".clickable-title\").each(function() {\n var title = $(this).attr(\"data-title\");\n if (title) {\n var tmp = document.createElement(\"DIV\");\n tmp.innerHTML = title;\n $(this).attr(\"title\", tmp.textContent || tmp.innerText || \"\");\n }\n });\n\n $(\".clickable-title\").click(function() {\n var title = $(this).attr(\"data-title\");\n if (title) {\n Codeforces.alert(title);\n } else {\n Codeforces.alert($(this).attr(\"title\"));\n }\n }).css(\"position\", \"relative\").css(\"bottom\", \"3px\");\n\n Codeforces.showDelayedMessage();\n\n Codeforces.reformatTimes();\n\n //Codeforces.initializePubSub();\n if (window.codeforcesOptions.subscribeServerUrl) {\n window.eventCatcher = new EventCatcher(\n window.codeforcesOptions.subscribeServerUrl,\n [\n Codeforces.getGlobalChannel(),\n Codeforces.getUserChannel(),\n Codeforces.getUserShowMessageChannel(),\n Codeforces.getContestChannel(),\n 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Codeforces.setupTutorials(\"/data/problemTutorial\");\n });\n </script>\n\n<script type=\"text/javascript\">\n var _gaq = _gaq || [];\n _gaq.push(['_setAccount', 'UA-743380-5']);\n _gaq.push(['_trackPageview']);\n\n (function () {\n var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;\n ga.src = (document.location.protocol == 'https:' ? 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/55\">Codeforces Beta Round 51</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='63dd214b3e5bea5ef119b79caa0ceea1'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/55/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Games, Sprague–Grundy theorem\">\r\n games\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1900\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='63dd214b3e5bea5ef119b79caa0ceea1'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"289\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='63dd214b3e5bea5ef119b79caa0ceea1'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"289\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1107\" title=\"Codeforces Beta Round #51\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"195:196\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1109\" title=\"Round 51, D\" target=\"_blank\">Round 51, D</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"197:198\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1113\" title=\"Round 51, E\" target=\"_blank\">Round 51, E</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"205:206\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1112\" title=\"Round 51, C\" target=\"_blank\">Round 51, C</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"203:204\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1111\" title=\"Round 51, B\" target=\"_blank\">Round 51, B</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"201:202\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1110\" title=\"Round 51, A\" target=\"_blank\">Round 51, A</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"199:200\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/55\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/55/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/55/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/55/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/55/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/55/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/55/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/55/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n 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Pie or die</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Volodya and Vlad play the following game. There are <span class=\"tex-span\"><i>k</i></span> pies at the cells of <span class=\"tex-span\"><i>n</i> × <i>m</i></span> board. Each turn Volodya moves one pie to the neighbouring (by side) cell. If the pie lies at the border of the board then Volodya can move it outside the board, get the pie and win. After Volodya's move, Vlad bans some edge at the border of the board of length 1 (between two knots of the board) so that Volodya is not able to move the pie outside the board through this edge anymore. The question is: will Volodya win this game? We suppose both players follow the optimal strategy.</p><center><img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/1878febc6260322dfe8bbc217a4ebbafa22eb482.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>First line contains 3 integers, separated by space: <span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 100</span> — dimensions of the board and <span class=\"tex-span\">0 ≤ <i>k</i> ≤ 100</span> — the number of pies. Each of the next <span class=\"tex-span\"><i>k</i></span> lines contains 2 integers, separated by space: <span class=\"tex-span\">1 ≤ <i>x</i> ≤ <i>n</i></span>, <span class=\"tex-span\">1 ≤ <i>y</i> ≤ <i>m</i></span> — coordinates of the corresponding pie. There could be more than one pie at a cell. </p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output only one word: "<span class=\"tex-font-style-tt\">YES</span>" — if Volodya wins, "<span class=\"tex-font-style-tt\">NO</span>" — otherwise.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2 1<br />1 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 4 0<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO</pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>100 50 2<br />50 25<br />50 25<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO</pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n 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\"*1900\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":287,"cells":{"problem_id":{"kind":"string","value":"55D"},"contest":{"kind":"string","value":"55"},"problem":{"kind":"string","value":"D"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"D. Beautiful numbers"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Beautiful numbers</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>4 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Volodya is an odd boy and his taste is strange as well. It seems to him that a positive integer number is <span class=\"tex-font-style-it\">beautiful</span> if and only if it is divisible by each of its nonzero digits. We will not argue with this and just count the quantity of beautiful numbers in given ranges.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line of the input contains the number of cases <span class=\"tex-span\"><i>t</i></span> (<span class=\"tex-span\">1 ≤ <i>t</i> ≤ 10</span>). Each of the next <span class=\"tex-span\"><i>t</i></span> lines contains two natural numbers <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>l</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>r</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 9 ·10<sup class=\"upper-index\">18</sup></span>).</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output should contain <span class=\"tex-span\"><i>t</i></span> numbers — answers to the queries, one number per line — quantities of beautiful numbers in given intervals (from <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> to <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>, inclusively).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>1 9<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1<br/>12 15<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"223fd7eb07d484e2c9d7aaaedeb5f12b\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"af37ad906831b23242765479fa0e0da4f3a2b149\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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#1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1113\" title=\"Round 51, E\" target=\"_blank\">Round 51, E</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"205:206\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1112\" title=\"Round 51, C\" target=\"_blank\">Round 51, C</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"203:204\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1111\" title=\"Round 51, B\" target=\"_blank\">Round 51, B</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"201:202\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1110\" title=\"Round 51, A\" target=\"_blank\">Round 51, A</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"199:200\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" 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}\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_28005456d74ad1617afa951841676304fa443254\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Beautiful numbers</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>4 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Volodya is an odd boy and his taste is strange as well. It seems to him that a positive integer number is <span class=\"tex-font-style-it\">beautiful</span> if and only if it is divisible by each of its nonzero digits. We will not argue with this and just count the quantity of beautiful numbers in given ranges.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line of the input contains the number of cases <span class=\"tex-span\"><i>t</i></span> (<span class=\"tex-span\">1 ≤ <i>t</i> ≤ 10</span>). Each of the next <span class=\"tex-span\"><i>t</i></span> lines contains two natural numbers <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>l</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>r</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 9 ·10<sup class=\"upper-index\">18</sup></span>).</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Output should contain <span class=\"tex-span\"><i>t</i></span> numbers — answers to the queries, one number per line — quantities of beautiful numbers in given intervals (from <span class=\"tex-span\"><i>l</i><sub class=\"lower-index\"><i>i</i></sub></span> to <span class=\"tex-span\"><i>r</i><sub class=\"lower-index\"><i>i</i></sub></span>, inclusively).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />1 9<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>1<br />12 15<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if (result[\"success\"] === \"true\") {\r\n Codeforces.facebox(\".diff-popup\", 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"},"long_tags":{"kind":"string","value":"[\"Dynamic programming\", \"Number theory: Euler function, GCD, divisibility, etc\"]"},"short_tags":{"kind":"string","value":"[\"dp\", \"number theory\", \"*2500\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":288,"cells":{"problem_id":{"kind":"string","value":"55E"},"contest":{"kind":"string","value":"55"},"problem":{"kind":"string","value":"E"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"E. Very simple problem"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Very simple problem</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>3 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You are given a convex polygon. Count, please, the number of triangles that contain a given point in the plane and their vertices are the vertices of the polygon. It is guaranteed, that the point doesn't lie on the sides and the diagonals of the polygon.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>n</i></span> — the number of vertices of the polygon (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 100000</span>). The polygon description is following: <span class=\"tex-span\"><i>n</i></span> lines containing coordinates of the vertices in clockwise order (integer <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> not greater than <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span> by absolute value). It is guaranteed that the given polygon is nondegenerate and convex (no three points lie on the same line).</p><p>The next line contains integer <span class=\"tex-span\"><i>t</i></span> (<span class=\"tex-span\">1 ≤ <i>t</i> ≤ 20</span>) — the number of points which you should count the answer for. It is followed by <span class=\"tex-span\"><i>t</i></span> lines with coordinates of the points (integer <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> not greater than <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span> by absolute value).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>The output should contain <span class=\"tex-span\"><i>t</i></span> integer numbers, each on a separate line, where <span class=\"tex-span\"><i>i</i></span>-th number is the answer for the <span class=\"tex-span\"><i>i</i></span>-th point.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>5 0<br/>0 0<br/>0 5<br/>5 5<br/>1<br/>1 3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/>0 0<br/>0 5<br/>5 0<br/>2<br/>1 1<br/>10 10<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/>0<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5<br/>7 6<br/>6 3<br/>4 1<br/>1 2<br/>2 4<br/>4<br/>3 3<br/>2 3<br/>5 5<br/>4 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br/>3<br/>3<br/>4<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"84ae5fde147a5d73a8d2a92d8740b3c1\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"af37ad906831b23242765479fa0e0da4f3a2b149\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/55\">Codeforces Beta Round 51</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/55/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Geometry, computational geometry\">\r\n geometry\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Two pointers\">\r\n two pointers\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *2500\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" 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Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1107\" title=\"Codeforces Beta Round #51\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"195:196\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1109\" title=\"Round 51, D\" target=\"_blank\">Round 51, D</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"197:198\" resourceName=\"Tutorial #1\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1113\" title=\"Round 51, E\" target=\"_blank\">Round 51, E</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"205:206\" resourceName=\"Tutorial #2\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1112\" title=\"Round 51, C\" target=\"_blank\">Round 51, C</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"203:204\" resourceName=\"Tutorial #3\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1111\" title=\"Round 51, B\" target=\"_blank\">Round 51, B</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"201:202\" resourceName=\"Tutorial #4\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1110\" title=\"Round 51, A\" target=\"_blank\">Round 51, A</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"199:200\" resourceName=\"Tutorial #5\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/55\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/55/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/55/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/55/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/55/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/55/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/55/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/55/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem 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(node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_b96cd832abd52dad9feb6011f8d9dad4d4cc94f2\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Very simple problem</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>3 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>You are given a convex polygon. Count, please, the number of triangles that contain a given point in the plane and their vertices are the vertices of the polygon. It is guaranteed, that the point doesn't lie on the sides and the diagonals of the polygon.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>n</i></span> — the number of vertices of the polygon (<span class=\"tex-span\">3 ≤ <i>n</i> ≤ 100000</span>). The polygon description is following: <span class=\"tex-span\"><i>n</i></span> lines containing coordinates of the vertices in clockwise order (integer <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> not greater than <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span> by absolute value). It is guaranteed that the given polygon is nondegenerate and convex (no three points lie on the same line).</p><p>The next line contains integer <span class=\"tex-span\"><i>t</i></span> (<span class=\"tex-span\">1 ≤ <i>t</i> ≤ 20</span>) — the number of points which you should count the answer for. It is followed by <span class=\"tex-span\"><i>t</i></span> lines with coordinates of the points (integer <span class=\"tex-span\"><i>x</i></span> and <span class=\"tex-span\"><i>y</i></span> not greater than <span class=\"tex-span\">10<sup class=\"upper-index\">9</sup></span> by absolute value).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>The output should contain <span class=\"tex-span\"><i>t</i></span> integer numbers, each on a separate line, where <span class=\"tex-span\"><i>i</i></span>-th number is the answer for the <span class=\"tex-span\"><i>i</i></span>-th point.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />5 0<br />0 0<br />0 5<br />5 5<br />1<br />1 3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br />0 0<br />0 5<br />5 0<br />2<br />1 1<br />10 10<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br />0<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>5<br />7 6<br />6 3<br />4 1<br />1 2<br />2 4<br />4<br />3 3<br />2 3<br />5 5<br />4 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br />3<br />3<br />4<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function 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\"*2500\"]"},"tutorial_link":{"kind":"string","value":""},"tutorial_page":{"kind":"string","value":""}}},{"rowIdx":289,"cells":{"problem_id":{"kind":"string","value":"56A"},"contest":{"kind":"string","value":"56"},"problem":{"kind":"string","value":"A"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"A. Bar"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Bar</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>According to Berland laws it is only allowed to sell alcohol to people <span class=\"tex-font-style-bf\">not younger than</span> 18 years. Vasya's job is to monitor the law's enforcement. Tonight he entered a bar and saw <span class=\"tex-span\"><i>n</i></span> people sitting there. For every one of them Vasya happened to determine either the age or the drink the person is having. Vasya can check any person, i.e. learn his age and the drink he is having at the same time. What minimal number of people should Vasya check additionally to make sure that there are no clients under 18 having alcohol drinks?</p><p>The list of all alcohol drinks in Berland is: <span class=\"tex-font-style-tt\">ABSINTH</span>, <span class=\"tex-font-style-tt\">BEER</span>, <span class=\"tex-font-style-tt\">BRANDY</span>, <span class=\"tex-font-style-tt\">CHAMPAGNE</span>, <span class=\"tex-font-style-tt\">GIN</span>, <span class=\"tex-font-style-tt\">RUM</span>, <span class=\"tex-font-style-tt\">SAKE</span>, <span class=\"tex-font-style-tt\">TEQUILA</span>, <span class=\"tex-font-style-tt\">VODKA</span>, <span class=\"tex-font-style-tt\">WHISKEY</span>, <span class=\"tex-font-style-tt\">WINE</span></p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100</span>) which is the number of the bar's clients. Then follow <span class=\"tex-span\"><i>n</i></span> lines, each describing one visitor. A line either contains his age (an integer from 0 to 1000) or his drink (a string of capital Latin letters from 1 to 100 in length). It is guaranteed that the input data does not contain spaces and other unnecessary separators.</p><p>Only the drinks from the list given above should be considered alcohol.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number which is the number of people Vasya should check to guarantee the law enforcement.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5<br/>18<br/>VODKA<br/>COKE<br/>19<br/>17<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the sample test the second and fifth clients should be checked.</p></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"f4a3b965c5dfabdcdf5ff049079a185e\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"0e30376a767efc57081ad269a3df436a8c3d78a2\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_96c3116d3e6d11b533525e91b4306c36475f60f4\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Bar</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>According to Berland laws it is only allowed to sell alcohol to people <span class=\"tex-font-style-bf\">not younger than</span> 18 years. Vasya's job is to monitor the law's enforcement. Tonight he entered a bar and saw <span class=\"tex-span\"><i>n</i></span> people sitting there. For every one of them Vasya happened to determine either the age or the drink the person is having. Vasya can check any person, i.e. learn his age and the drink he is having at the same time. What minimal number of people should Vasya check additionally to make sure that there are no clients under 18 having alcohol drinks?</p><p>The list of all alcohol drinks in Berland is: <span class=\"tex-font-style-tt\">ABSINTH</span>, <span class=\"tex-font-style-tt\">BEER</span>, <span class=\"tex-font-style-tt\">BRANDY</span>, <span class=\"tex-font-style-tt\">CHAMPAGNE</span>, <span class=\"tex-font-style-tt\">GIN</span>, <span class=\"tex-font-style-tt\">RUM</span>, <span class=\"tex-font-style-tt\">SAKE</span>, <span class=\"tex-font-style-tt\">TEQUILA</span>, <span class=\"tex-font-style-tt\">VODKA</span>, <span class=\"tex-font-style-tt\">WHISKEY</span>, <span class=\"tex-font-style-tt\">WINE</span></p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 100</span>) which is the number of the bar's clients. Then follow <span class=\"tex-span\"><i>n</i></span> lines, each describing one visitor. A line either contains his age (an integer from 0 to 1000) or his drink (a string of capital Latin letters from 1 to 100 in length). It is guaranteed that the input data does not contain spaces and other unnecessary separators.</p><p>Only the drinks from the list given above should be considered alcohol.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number which is the number of people Vasya should check to guarantee the law enforcement.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5<br />18<br />VODKA<br />COKE<br />19<br />17<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br /></pre></div></div></div><div class=\"note\"><div class=\"section-title\">Note</div><p>In the sample test the second and fifth clients should be checked.</p></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" 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class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1ad8da0aaf90aa865343cab51d7160ca'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/pkhaustov\">pkhaustov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/pkhaustov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/pkhaustov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/pkhaustov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/pkhaustov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/pkhaustov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/pkhaustov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/pkhaustov\" style=\"text-decoration:none;color:black !important;\">pkhaustov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1147\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1147\"> CodeForces Beta Round #52 :: Разбор задач\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/pkhaustov\" title=\"Master pkhaustov\" class=\"rated-user user-orange\">pkhaustov</a>,\r\n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Задача А. Бар</b></div><div>Ответом на задачу является количество посетителей, которые удовлетворяют одному из предложенных ограничений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Указан возраст посетителя и он меньше 18 лет</i></div></div><div><div><i>2) Указан напиток посетителя и он является алкогольным</i></div></div></blockquote><div><div>Далее остается аккуратная реализация.</div><div><br /></div><div><b>Задача B. Испорченная перестановка</b></div><div>Задача имеет множество решений. В разборе будет расказанно решение с асимптотикой O(N), где N - количество элементов последовательности.</div><div>Найдем такое наименьшее i, такое что A<sub>i</sub> не равно i (элементы нумеруются с единицы). Если такого i не существует, то все числа стоят на своих местах и, соответственно, ответом являются два нуля. Иначе, предполагаем, что ответом являются числа i и A<sub>i</sub> (мы можем быть точно уверены, что i < A<sub>i</sub>). Переворачиваем подпоследовательность элементов с i-ого по A<sub>i</sub>-ый и проверяем всю полученную последовательность на то, везде ли A<sub>i</sub> равно i. Если да, то ответом является пара (i, A<sub>i</sub>), иначе ответ - два нуля.</div><div><br /></div><div><b>Задача C. Почта в корпорации</b></div><div>Для решения задачи вполне подходит решение за O(N<sup>2</sup>L), где N - количество людей в иерархии, а L - средняя длина имени сотрудника. То есть сравнение строк можно выполнять без использования хэш-функции.</div><div>Первая часть решения - аккуратная реализация примитивного парсинга строки. Наиболее простой способ - рекурсивная функция, которая читает сначала имя сотрудника, а потом и всех его подчиненных до тех пор, пока не достигнет точки. Далее потребуется хранить в памяти дерево из N вершин. Хранение дерева можно организовать как с помощью динамической памяти, так и простой матрицей смежности. Далее можно просто для каждой вершины запустить обход в глубину из нее и посмотреть скольким вершинам в этом поддереве сопоставлено такое же имя. Стоит обратить внимание на то, что сама вершина, из которой изначально запускается обход в глубину, не должна быть посчитана в ответ.</div><div>Такое решение можно улучшить до сложности O(NlogN), используя хэширование и более сложные структуры данных (например map). При данных ограничениях это было бы пустой тратой времени. Даже грубой оценки N < 500 достаточно, чтобы решение уложилось в time limit.</div><div><br /></div><div><b>Задача D. Получаем строку</b></div><div>Наиболее простым решением этой задачи является решение с использованием динамического программирования. Обозначим первую строку за A, а вторую за B. Длина первой строки равна N, а второй - M. Тогда решение имеет асимптотику O(NM).</div><div>Обозначим за S(i, j) - подстроку строки S с i-ого по j-ый символ.</div><div>Введем функцию F(x, y) - сколько минимум действий надо выполнить, чтобы из подстроки A(x, N - 1) получить подстроку B(y, M - 1) (индексы символов нумеруются с нуля). Тогда значание F(x, y) это минимум из:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>F(x + 1, y + 1), при x < N, y < M и A[x] = B[x]</i></div></div><div><div><i>F(x + 1, y + 1) + 1, при x < N, y < M</i></div></div><div><div><i>F(x + 1, y), при x < N</i></div></div><div><div><i>F(x, y + 1), при y < M</i></div></div></blockquote><div><div>Очевидно, что F(N, M) равно нулю.</div><div>Если при обработке очередного перехода не только обновлять значение функции, но и запоминать тип перехода, то по окончании подсчета функции F(0, 0) можно будет восстановить набор необходимых операций для превращения строки A в строку B. Ну а само значение F(0, 0) и будет искомым ответом.</div><div><br /></div><div><b>Задача E. Принцип домино</b></div><div>Задача вполне может иметь множество решений, но в данном разборе будет рассказано одно из наиболее тривиальных.</div><div>Для начала отсортируем все доминошки по координате x слева направо, запомнив изначальную нумерацию. Эта нумерация потребуется только для вывода ответа в правильном порядке. Далее нужно сформулировать несколько тривиальных утверждений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Если толкнуть какую-либо доминошку вправо, то среди упавших доминошек все (кроме самой доминошки) будут находиться справа от той, что толкнули.</i></div></div><div><div><i>2) Если какая-либо доминошка упала, то упали и все доминошки, которые находятся левее этой, но не левее той, что изначально толкнули.</i></div></div><div><div><i>3) Для каждой доминошки можно определить номер наиболее правой доминошки такой, что она упадет, если толкнуть данную.</i></div></div></blockquote><div><div>Обозначим за F(i) номер наиболее правой доминошки, которая упадет, если толкнуть i-ую доминошку. Сама по себе i-ая доминошка может не упасть на F(i)-ую, но из-за "принципа домино" F(i)-ая все же упадет. Если доминошка при падении вообще не задевает никакую другую доминошку, то F(i) = i. Очевидно, что такое равенство выполняется для самой правой доминошки. Для остальных доминошек можно найти значение F(i) с помощью уже найденных F(j), где j > i.</div><div>Для каждой доминошки с номером i можно найти такую доминошку с номером j, что при падении i-ая повалит j-ую (непосредственно), и такое j максимально. То есть найти самую правую из доминошек, которую повалит непосредственно i-ая. Далее F(i) = max(F(k)), где k принимает значения на интервале [i + 1, j].</div><div>Реализация решения с асимптотикой O(N<sup>2</sup>) точно не влезет в ограничения по времени. Поэтому необходимо написать решение как минимум за O(NlogN), для чего достаточно воспользоваться структурой данных типа дерева интервалов. Короче говоря, решить задачу Range Maximum Query.</div></div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1558-1147\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1558\",\n blogEntryId: \"1147\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+%2352\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round #52</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80+%D0%B7%D0%B0%D0%B4%D0%B0%D1%87\" class=\"tag notice\" style=\"text-decoration: none;\">разбор задач</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+18</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/pkhaustov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/pkhaustov\">\n pkhaustov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1147#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1147#comments\">\n 7\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1157\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (7)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"503605\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/StayFocus\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/StayFocus\" title=\"Expert StayFocus\" class=\"rated-user user-blue\">StayFocus</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Apr/02/2019 17:19\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-503605\" href=\"?#comment-503605\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"503605\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"870984\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-503605\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>How I use the segment tree to solve problem E ???</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-503605 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-503605 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-503605\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"648445\" commentParentId=\"503605\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/lucifer1004\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1200541/avatar/407a3847bec8a7ec.jpg'/> </a>\n <div><a href=\"/profile/lucifer1004\" title=\"Master lucifer1004\" class=\"rated-user user-orange\">lucifer1004</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jun/23/2020 16:53\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-648445\" href=\"?#comment-648445\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-503605\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"648445\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1200541\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-648445\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>You just need to implement a segment tree which supports single assignment and range minimum query. Since there is no range modification, no lazy propagation is needed, and the segment tree implementation is very simple.</p><p>For the other part, you can just refer to the tutorial.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-648445 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-648445 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-648445\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"727707\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/proudnerd99\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1648278/avatar/375c144d797bf903.jpg'/> </a>\n <div><a href=\"/profile/proudnerd99\" title=\"Expert proudnerd99\" class=\"rated-user user-blue\">proudnerd99</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Nov/30/2020 16:51\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-727707\" href=\"?#comment-727707\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"727707\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"727707\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1648278\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-727707\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>For those of us who don't understand russian, if you are looking for a solution of D, then refer <a href=\"http://www.geeksforgeeks.org/edit-distance-dp-5/\">here:</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-727707 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-727707 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-727707\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"930877\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jul/12/2022 19:19\">15 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-930877\" href=\"?#comment-930877\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"930877\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-930877\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>E Problem can actually be written in a much easier manner(at least I think so :D). You can use dynamic programming. let us create an array dp initialized with 1-s, which will contain how many dominoes can i-th domino flip. we also use another array where on i-th index is written x, which is index of a domino which will not fall if you trip i-th domino. lets call domino with index x barrier of i-th domino. first you sort the pairs by coordinates. Then you go from end to beginning and implement logic:</p><p>1) if i-th domino can cause i+1 to fall, you do dp[i] += dp[i+1]. after this you check if i-th domino can reach i+1-th domino's barrier, if yes dp[i] += dp[x] and then you check x-th domino's barrier and so on. when you find i-th domino's barrier you save it in the second array. we can see that now barrier can only be i-th domino or its barrier(or everything else on its right), so after next iterations we wont have to check dominoes in between. 2) if i-th domino can't flip domino on its right we just save i+1 as i-th domino's barrier.</p><p>sorting will take O(nlogn) and the solution with dp O(n).</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-930877 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-930877 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-930877\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"956835\" commentParentId=\"930877\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/ISeeDS-V2.0\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/ISeeDS-V2.0\" title=\"Specialist ISeeDS-V2.0\" class=\"rated-user user-cyan\">ISeeDS-V2.0</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Sep/27/2022 15:41\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-956835\" href=\"?#comment-956835\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-930877\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"956835\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"2471287\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-956835\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>could you show insert a code link please?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-956835 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-956835 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-956835\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"963107\" commentParentId=\"956835\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/14/2022 16:45\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-963107\" href=\"?#comment-963107\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-956835\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"963107\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-963107\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Here you go: <a href=\"https://github.com/datobena/Algorithms/blob/master/codeforces/56E.cpp\">Code</a>.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-963107 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-963107 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-963107\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"1054419\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/gaurav_436310\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1962290/avatar/cc0070bed7de61db.jpg'/> </a>\n <div><a href=\"/profile/gaurav_436310\" title=\"Newbie gaurav_436310\" class=\"rated-user user-gray\">gaurav_436310</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Aug/02/2023 14:03\">2 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-1054419\" href=\"?#comment-1054419\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"1054419\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1962290\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-1054419\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Where can I find the English version of this editorial?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-1054419 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-1054419 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-1054419\">\r\n </ul>\r\n</div>\r\n 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Spoilt Permutation"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Spoilt Permutation</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya collects coins: he has exactly one coin for every year from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. Naturally, Vasya keeps all the coins in his collection in the order in which they were released. Once Vasya's younger brother made a change — he took all the coins whose release year dated from <span class=\"tex-span\"><i>l</i></span> to <span class=\"tex-span\"><i>r</i></span> inclusively and put them in the reverse order. That is, he took a certain segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> and reversed it. At that the segment's endpoints did not coincide. For example, if <span class=\"tex-span\"><i>n</i> = 8</span>, then initially Vasya's coins were kept in the order <span class=\"tex-font-style-tt\">1 2 3 4 5 6 7 8</span>. If Vasya's younger brother chose the segment <span class=\"tex-span\">[2, 6]</span>, then after the reversal the coin order will change to <span class=\"tex-font-style-tt\">1 6 5 4 3 2 7 8</span>. Vasya suspects that someone else could have spoilt the permutation after his brother. Help him to find that out. Check if the given permutation can be obtained from the permutation <span class=\"tex-font-style-tt\">1 2 ... <span class=\"tex-span\"><i>n</i></span></span> using exactly one segment reversal. If it is possible, find the segment itself.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 1000</span>) which is the number of coins in Vasya's collection. The second line contains space-separated <span class=\"tex-span\"><i>n</i></span> integers which are the spoilt sequence of coins. It is guaranteed that the given sequence is a permutation, i.e. it contains only integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, and every number is used exactly 1 time.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If it is impossible to obtain the given permutation from the original one in exactly one action, print <span class=\"tex-font-style-tt\">0 0</span>. Otherwise, print two numbers <span class=\"tex-span\"><i>l</i></span> <span class=\"tex-span\"><i>r</i></span> (<span class=\"tex-span\">1 ≤ <i>l</i> < <i>r</i> ≤ <i>n</i></span>) which are the endpoints of the segment that needs to be reversed to obtain from permutation <span class=\"tex-font-style-tt\">1 2 ... <span class=\"tex-span\"><i>n</i></span></span> the given one.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>8<br/>1 6 5 4 3 2 7 8<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 6<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>2 3 4 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0 0<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>1 2 3 4<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0 0<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"36dec37a61439931d6547b541c094754\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"0e30376a767efc57081ad269a3df436a8c3d78a2\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"B\" data-uuid=\"ps_4b2104daab43000d1dd2210d21e243c97bf36cf5\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Spoilt Permutation</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya collects coins: he has exactly one coin for every year from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. Naturally, Vasya keeps all the coins in his collection in the order in which they were released. Once Vasya's younger brother made a change — he took all the coins whose release year dated from <span class=\"tex-span\"><i>l</i></span> to <span class=\"tex-span\"><i>r</i></span> inclusively and put them in the reverse order. That is, he took a certain segment <span class=\"tex-span\">[<i>l</i>, <i>r</i>]</span> and reversed it. At that the segment's endpoints did not coincide. For example, if <span class=\"tex-span\"><i>n</i> = 8</span>, then initially Vasya's coins were kept in the order <span class=\"tex-font-style-tt\">1 2 3 4 5 6 7 8</span>. If Vasya's younger brother chose the segment <span class=\"tex-span\">[2, 6]</span>, then after the reversal the coin order will change to <span class=\"tex-font-style-tt\">1 6 5 4 3 2 7 8</span>. Vasya suspects that someone else could have spoilt the permutation after his brother. Help him to find that out. Check if the given permutation can be obtained from the permutation <span class=\"tex-font-style-tt\">1 2 ... <span class=\"tex-span\"><i>n</i></span></span> using exactly one segment reversal. If it is possible, find the segment itself.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains an integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 1000</span>) which is the number of coins in Vasya's collection. The second line contains space-separated <span class=\"tex-span\"><i>n</i></span> integers which are the spoilt sequence of coins. It is guaranteed that the given sequence is a permutation, i.e. it contains only integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>, and every number is used exactly 1 time.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If it is impossible to obtain the given permutation from the original one in exactly one action, print <span class=\"tex-font-style-tt\">0 0</span>. Otherwise, print two numbers <span class=\"tex-span\"><i>l</i></span> <span class=\"tex-span\"><i>r</i></span> (<span class=\"tex-span\">1 ≤ <i>l</i> < <i>r</i> ≤ <i>n</i></span>) which are the endpoints of the segment that needs to be reversed to obtain from permutation <span class=\"tex-font-style-tt\">1 2 ... <span class=\"tex-span\"><i>n</i></span></span> the given one.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>8<br />1 6 5 4 3 2 7 8<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2 6<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />2 3 4 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0 0<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />1 2 3 4<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0 0<br 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:49</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" 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class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1ad8da0aaf90aa865343cab51d7160ca'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/pkhaustov\">pkhaustov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/pkhaustov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/pkhaustov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/pkhaustov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/pkhaustov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/pkhaustov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/pkhaustov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/pkhaustov\" style=\"text-decoration:none;color:black !important;\">pkhaustov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1147\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1147\"> CodeForces Beta Round #52 :: Разбор задач\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/pkhaustov\" title=\"Master pkhaustov\" class=\"rated-user user-orange\">pkhaustov</a>,\r\n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Задача А. Бар</b></div><div>Ответом на задачу является количество посетителей, которые удовлетворяют одному из предложенных ограничений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Указан возраст посетителя и он меньше 18 лет</i></div></div><div><div><i>2) Указан напиток посетителя и он является алкогольным</i></div></div></blockquote><div><div>Далее остается аккуратная реализация.</div><div><br /></div><div><b>Задача B. Испорченная перестановка</b></div><div>Задача имеет множество решений. В разборе будет расказанно решение с асимптотикой O(N), где N - количество элементов последовательности.</div><div>Найдем такое наименьшее i, такое что A<sub>i</sub> не равно i (элементы нумеруются с единицы). Если такого i не существует, то все числа стоят на своих местах и, соответственно, ответом являются два нуля. Иначе, предполагаем, что ответом являются числа i и A<sub>i</sub> (мы можем быть точно уверены, что i < A<sub>i</sub>). Переворачиваем подпоследовательность элементов с i-ого по A<sub>i</sub>-ый и проверяем всю полученную последовательность на то, везде ли A<sub>i</sub> равно i. Если да, то ответом является пара (i, A<sub>i</sub>), иначе ответ - два нуля.</div><div><br /></div><div><b>Задача C. Почта в корпорации</b></div><div>Для решения задачи вполне подходит решение за O(N<sup>2</sup>L), где N - количество людей в иерархии, а L - средняя длина имени сотрудника. То есть сравнение строк можно выполнять без использования хэш-функции.</div><div>Первая часть решения - аккуратная реализация примитивного парсинга строки. Наиболее простой способ - рекурсивная функция, которая читает сначала имя сотрудника, а потом и всех его подчиненных до тех пор, пока не достигнет точки. Далее потребуется хранить в памяти дерево из N вершин. Хранение дерева можно организовать как с помощью динамической памяти, так и простой матрицей смежности. Далее можно просто для каждой вершины запустить обход в глубину из нее и посмотреть скольким вершинам в этом поддереве сопоставлено такое же имя. Стоит обратить внимание на то, что сама вершина, из которой изначально запускается обход в глубину, не должна быть посчитана в ответ.</div><div>Такое решение можно улучшить до сложности O(NlogN), используя хэширование и более сложные структуры данных (например map). При данных ограничениях это было бы пустой тратой времени. Даже грубой оценки N < 500 достаточно, чтобы решение уложилось в time limit.</div><div><br /></div><div><b>Задача D. Получаем строку</b></div><div>Наиболее простым решением этой задачи является решение с использованием динамического программирования. Обозначим первую строку за A, а вторую за B. Длина первой строки равна N, а второй - M. Тогда решение имеет асимптотику O(NM).</div><div>Обозначим за S(i, j) - подстроку строки S с i-ого по j-ый символ.</div><div>Введем функцию F(x, y) - сколько минимум действий надо выполнить, чтобы из подстроки A(x, N - 1) получить подстроку B(y, M - 1) (индексы символов нумеруются с нуля). Тогда значание F(x, y) это минимум из:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>F(x + 1, y + 1), при x < N, y < M и A[x] = B[x]</i></div></div><div><div><i>F(x + 1, y + 1) + 1, при x < N, y < M</i></div></div><div><div><i>F(x + 1, y), при x < N</i></div></div><div><div><i>F(x, y + 1), при y < M</i></div></div></blockquote><div><div>Очевидно, что F(N, M) равно нулю.</div><div>Если при обработке очередного перехода не только обновлять значение функции, но и запоминать тип перехода, то по окончании подсчета функции F(0, 0) можно будет восстановить набор необходимых операций для превращения строки A в строку B. Ну а само значение F(0, 0) и будет искомым ответом.</div><div><br /></div><div><b>Задача E. Принцип домино</b></div><div>Задача вполне может иметь множество решений, но в данном разборе будет рассказано одно из наиболее тривиальных.</div><div>Для начала отсортируем все доминошки по координате x слева направо, запомнив изначальную нумерацию. Эта нумерация потребуется только для вывода ответа в правильном порядке. Далее нужно сформулировать несколько тривиальных утверждений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Если толкнуть какую-либо доминошку вправо, то среди упавших доминошек все (кроме самой доминошки) будут находиться справа от той, что толкнули.</i></div></div><div><div><i>2) Если какая-либо доминошка упала, то упали и все доминошки, которые находятся левее этой, но не левее той, что изначально толкнули.</i></div></div><div><div><i>3) Для каждой доминошки можно определить номер наиболее правой доминошки такой, что она упадет, если толкнуть данную.</i></div></div></blockquote><div><div>Обозначим за F(i) номер наиболее правой доминошки, которая упадет, если толкнуть i-ую доминошку. Сама по себе i-ая доминошка может не упасть на F(i)-ую, но из-за "принципа домино" F(i)-ая все же упадет. Если доминошка при падении вообще не задевает никакую другую доминошку, то F(i) = i. Очевидно, что такое равенство выполняется для самой правой доминошки. Для остальных доминошек можно найти значение F(i) с помощью уже найденных F(j), где j > i.</div><div>Для каждой доминошки с номером i можно найти такую доминошку с номером j, что при падении i-ая повалит j-ую (непосредственно), и такое j максимально. То есть найти самую правую из доминошек, которую повалит непосредственно i-ая. Далее F(i) = max(F(k)), где k принимает значения на интервале [i + 1, j].</div><div>Реализация решения с асимптотикой O(N<sup>2</sup>) точно не влезет в ограничения по времени. Поэтому необходимо написать решение как минимум за O(NlogN), для чего достаточно воспользоваться структурой данных типа дерева интервалов. Короче говоря, решить задачу Range Maximum Query.</div></div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1558-1147\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1558\",\n blogEntryId: \"1147\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+%2352\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round #52</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80+%D0%B7%D0%B0%D0%B4%D0%B0%D1%87\" class=\"tag notice\" style=\"text-decoration: none;\">разбор задач</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+18</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/pkhaustov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/pkhaustov\">\n pkhaustov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1147#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1147#comments\">\n 7\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1157\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (7)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"503605\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/StayFocus\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/StayFocus\" title=\"Expert StayFocus\" class=\"rated-user user-blue\">StayFocus</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Apr/02/2019 17:19\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-503605\" href=\"?#comment-503605\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"503605\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"870984\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-503605\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>How I use the segment tree to solve problem E ???</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-503605 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-503605 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-503605\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"648445\" commentParentId=\"503605\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/lucifer1004\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1200541/avatar/407a3847bec8a7ec.jpg'/> </a>\n <div><a href=\"/profile/lucifer1004\" title=\"Master lucifer1004\" class=\"rated-user user-orange\">lucifer1004</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jun/23/2020 16:53\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-648445\" href=\"?#comment-648445\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-503605\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"648445\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1200541\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-648445\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>You just need to implement a segment tree which supports single assignment and range minimum query. Since there is no range modification, no lazy propagation is needed, and the segment tree implementation is very simple.</p><p>For the other part, you can just refer to the tutorial.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-648445 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-648445 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-648445\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"727707\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/proudnerd99\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1648278/avatar/375c144d797bf903.jpg'/> </a>\n <div><a href=\"/profile/proudnerd99\" title=\"Expert proudnerd99\" class=\"rated-user user-blue\">proudnerd99</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Nov/30/2020 16:51\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-727707\" href=\"?#comment-727707\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"727707\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"727707\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1648278\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-727707\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>For those of us who don't understand russian, if you are looking for a solution of D, then refer <a href=\"http://www.geeksforgeeks.org/edit-distance-dp-5/\">here:</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-727707 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-727707 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-727707\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"930877\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jul/12/2022 19:19\">15 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-930877\" href=\"?#comment-930877\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"930877\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-930877\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>E Problem can actually be written in a much easier manner(at least I think so :D). You can use dynamic programming. let us create an array dp initialized with 1-s, which will contain how many dominoes can i-th domino flip. we also use another array where on i-th index is written x, which is index of a domino which will not fall if you trip i-th domino. lets call domino with index x barrier of i-th domino. first you sort the pairs by coordinates. Then you go from end to beginning and implement logic:</p><p>1) if i-th domino can cause i+1 to fall, you do dp[i] += dp[i+1]. after this you check if i-th domino can reach i+1-th domino's barrier, if yes dp[i] += dp[x] and then you check x-th domino's barrier and so on. when you find i-th domino's barrier you save it in the second array. we can see that now barrier can only be i-th domino or its barrier(or everything else on its right), so after next iterations we wont have to check dominoes in between. 2) if i-th domino can't flip domino on its right we just save i+1 as i-th domino's barrier.</p><p>sorting will take O(nlogn) and the solution with dp O(n).</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-930877 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-930877 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-930877\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"956835\" commentParentId=\"930877\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/ISeeDS-V2.0\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/ISeeDS-V2.0\" title=\"Specialist ISeeDS-V2.0\" class=\"rated-user user-cyan\">ISeeDS-V2.0</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Sep/27/2022 15:41\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-956835\" href=\"?#comment-956835\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-930877\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"956835\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"2471287\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-956835\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>could you show insert a code link please?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-956835 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-956835 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-956835\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"963107\" commentParentId=\"956835\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/14/2022 16:45\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-963107\" href=\"?#comment-963107\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-956835\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"963107\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-963107\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Here you go: <a href=\"https://github.com/datobena/Algorithms/blob/master/codeforces/56E.cpp\">Code</a>.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-963107 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-963107 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-963107\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"1054419\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/gaurav_436310\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1962290/avatar/cc0070bed7de61db.jpg'/> </a>\n <div><a href=\"/profile/gaurav_436310\" title=\"Newbie gaurav_436310\" class=\"rated-user user-gray\">gaurav_436310</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Aug/02/2023 14:03\">2 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-1054419\" href=\"?#comment-1054419\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"1054419\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1962290\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-1054419\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Where can I find the English version of this editorial?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-1054419 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-1054419 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-1054419\">\r\n </ul>\r\n</div>\r\n 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Corporation Mail"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Corporation Mail</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Beroil corporation structure is hierarchical, that is it can be represented as a tree. Let's examine the presentation of this structure as follows:</p><ul> <li> <span class=\"tex-span\"><i>employee</i></span> ::= <span class=\"tex-span\"><i>name</i></span><span class=\"tex-font-style-tt\">.</span> | <span class=\"tex-span\"><i>name</i></span><span class=\"tex-font-style-tt\">:</span><span class=\"tex-span\"><i>employee</i><sub class=\"lower-index\">1</sub></span><span class=\"tex-font-style-tt\">,</span><span class=\"tex-span\"><i>employee</i><sub class=\"lower-index\">2</sub></span><span class=\"tex-font-style-tt\">,</span> ... <span class=\"tex-font-style-tt\">,</span><span class=\"tex-span\"><i>employee</i><sub class=\"lower-index\"><i>k</i></sub></span><span class=\"tex-font-style-tt\">.</span> </li><li> <span class=\"tex-span\"><i>name</i></span> ::= name of an employee </li></ul><p>That is, the description of each employee consists of his name, a colon (<span class=\"tex-font-style-tt\">:</span>), the descriptions of all his subordinates separated by commas, and, finally, a dot. If an employee has no subordinates, then the colon is not present in his description.</p><p>For example, line <span class=\"tex-font-style-tt\">MIKE:MAX.,ARTEM:MIKE..,DMITRY:DMITRY.,DMITRY...</span> is the correct way of recording the structure of a corporation where the director <span class=\"tex-font-style-tt\">MIKE</span> has subordinates <span class=\"tex-font-style-tt\">MAX</span>, <span class=\"tex-font-style-tt\">ARTEM</span> and <span class=\"tex-font-style-tt\">DMITRY</span>. <span class=\"tex-font-style-tt\">ARTEM</span> has a subordinate whose name is <span class=\"tex-font-style-tt\">MIKE</span>, just as the name of his boss and two subordinates of <span class=\"tex-font-style-tt\">DMITRY</span> are called <span class=\"tex-font-style-tt\">DMITRY</span>, just like himself.</p><p>In the Beroil corporation every employee can only correspond with his subordinates, at that the subordinates are not necessarily direct. Let's call an uncomfortable situation the situation when a person whose name is <span class=\"tex-span\"><i>s</i></span> writes a letter to another person whose name is also <span class=\"tex-span\"><i>s</i></span>. In the example given above are two such pairs: a pair involving <span class=\"tex-font-style-tt\">MIKE</span>, and two pairs for <span class=\"tex-font-style-tt\">DMITRY</span> (a pair for each of his subordinates).</p><p>Your task is by the given structure of the corporation to find the number of uncomfortable pairs in it.</p><center><img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/11018622b70b7e278e6c9c9b7569a62fe1de9e39.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/></center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first and single line contains the corporation structure which is a string of length from 1 to 1000 characters. It is guaranteed that the description is correct. Every name is a string consisting of capital Latin letters from 1 to 10 symbols in length.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number — the number of uncomfortable situations in the company.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>MIKE:MAX.,ARTEM:MIKE..,DMITRY:DMITRY.,DMITRY...<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>A:A..<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>A:C:C:C:C.....<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"cacce5beb0c3426d0e770d158538e0c5\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"0e30376a767efc57081ad269a3df436a8c3d78a2\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_94e298541a5590775c70b60cfaf2700a091d3d08\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Corporation Mail</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>The Beroil corporation structure is hierarchical, that is it can be represented as a tree. Let's examine the presentation of this structure as follows:</p><ul> <li> <span class=\"tex-span\"><i>employee</i></span> ::= <span class=\"tex-span\"><i>name</i></span><span class=\"tex-font-style-tt\">.</span> | <span class=\"tex-span\"><i>name</i></span><span class=\"tex-font-style-tt\">:</span><span class=\"tex-span\"><i>employee</i><sub class=\"lower-index\">1</sub></span><span class=\"tex-font-style-tt\">,</span><span class=\"tex-span\"><i>employee</i><sub class=\"lower-index\">2</sub></span><span class=\"tex-font-style-tt\">,</span> ... <span class=\"tex-font-style-tt\">,</span><span class=\"tex-span\"><i>employee</i><sub class=\"lower-index\"><i>k</i></sub></span><span class=\"tex-font-style-tt\">.</span> </li><li> <span class=\"tex-span\"><i>name</i></span> ::= name of an employee </li></ul><p>That is, the description of each employee consists of his name, a colon (<span class=\"tex-font-style-tt\">:</span>), the descriptions of all his subordinates separated by commas, and, finally, a dot. If an employee has no subordinates, then the colon is not present in his description.</p><p>For example, line <span class=\"tex-font-style-tt\">MIKE:MAX.,ARTEM:MIKE..,DMITRY:DMITRY.,DMITRY...</span> is the correct way of recording the structure of a corporation where the director <span class=\"tex-font-style-tt\">MIKE</span> has subordinates <span class=\"tex-font-style-tt\">MAX</span>, <span class=\"tex-font-style-tt\">ARTEM</span> and <span class=\"tex-font-style-tt\">DMITRY</span>. <span class=\"tex-font-style-tt\">ARTEM</span> has a subordinate whose name is <span class=\"tex-font-style-tt\">MIKE</span>, just as the name of his boss and two subordinates of <span class=\"tex-font-style-tt\">DMITRY</span> are called <span class=\"tex-font-style-tt\">DMITRY</span>, just like himself.</p><p>In the Beroil corporation every employee can only correspond with his subordinates, at that the subordinates are not necessarily direct. Let's call an uncomfortable situation the situation when a person whose name is <span class=\"tex-span\"><i>s</i></span> writes a letter to another person whose name is also <span class=\"tex-span\"><i>s</i></span>. In the example given above are two such pairs: a pair involving <span class=\"tex-font-style-tt\">MIKE</span>, and two pairs for <span class=\"tex-font-style-tt\">DMITRY</span> (a pair for each of his subordinates).</p><p>Your task is by the given structure of the corporation to find the number of uncomfortable pairs in it.</p><center><img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/11018622b70b7e278e6c9c9b7569a62fe1de9e39.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first and single line contains the corporation structure which is a string of length from 1 to 1000 characters. It is guaranteed that the description is correct. Every name is a string consisting of capital Latin letters from 1 to 10 symbols in length.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print a single number — the number of uncomfortable situations in the company.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>MIKE:MAX.,ARTEM:MIKE..,DMITRY:DMITRY.,DMITRY...<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>A:A..<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>A:C:C:C:C.....<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:49</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1ad8da0aaf90aa865343cab51d7160ca'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div 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class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New 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title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/pkhaustov\">pkhaustov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/pkhaustov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/pkhaustov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/pkhaustov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/pkhaustov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/pkhaustov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/pkhaustov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/pkhaustov\" style=\"text-decoration:none;color:black !important;\">pkhaustov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1147\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1147\"> CodeForces Beta Round #52 :: Разбор задач\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/pkhaustov\" title=\"Master pkhaustov\" class=\"rated-user user-orange\">pkhaustov</a>,\r\n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Задача А. Бар</b></div><div>Ответом на задачу является количество посетителей, которые удовлетворяют одному из предложенных ограничений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Указан возраст посетителя и он меньше 18 лет</i></div></div><div><div><i>2) Указан напиток посетителя и он является алкогольным</i></div></div></blockquote><div><div>Далее остается аккуратная реализация.</div><div><br /></div><div><b>Задача B. Испорченная перестановка</b></div><div>Задача имеет множество решений. В разборе будет расказанно решение с асимптотикой O(N), где N - количество элементов последовательности.</div><div>Найдем такое наименьшее i, такое что A<sub>i</sub> не равно i (элементы нумеруются с единицы). Если такого i не существует, то все числа стоят на своих местах и, соответственно, ответом являются два нуля. Иначе, предполагаем, что ответом являются числа i и A<sub>i</sub> (мы можем быть точно уверены, что i < A<sub>i</sub>). Переворачиваем подпоследовательность элементов с i-ого по A<sub>i</sub>-ый и проверяем всю полученную последовательность на то, везде ли A<sub>i</sub> равно i. Если да, то ответом является пара (i, A<sub>i</sub>), иначе ответ - два нуля.</div><div><br /></div><div><b>Задача C. Почта в корпорации</b></div><div>Для решения задачи вполне подходит решение за O(N<sup>2</sup>L), где N - количество людей в иерархии, а L - средняя длина имени сотрудника. То есть сравнение строк можно выполнять без использования хэш-функции.</div><div>Первая часть решения - аккуратная реализация примитивного парсинга строки. Наиболее простой способ - рекурсивная функция, которая читает сначала имя сотрудника, а потом и всех его подчиненных до тех пор, пока не достигнет точки. Далее потребуется хранить в памяти дерево из N вершин. Хранение дерева можно организовать как с помощью динамической памяти, так и простой матрицей смежности. Далее можно просто для каждой вершины запустить обход в глубину из нее и посмотреть скольким вершинам в этом поддереве сопоставлено такое же имя. Стоит обратить внимание на то, что сама вершина, из которой изначально запускается обход в глубину, не должна быть посчитана в ответ.</div><div>Такое решение можно улучшить до сложности O(NlogN), используя хэширование и более сложные структуры данных (например map). При данных ограничениях это было бы пустой тратой времени. Даже грубой оценки N < 500 достаточно, чтобы решение уложилось в time limit.</div><div><br /></div><div><b>Задача D. Получаем строку</b></div><div>Наиболее простым решением этой задачи является решение с использованием динамического программирования. Обозначим первую строку за A, а вторую за B. Длина первой строки равна N, а второй - M. Тогда решение имеет асимптотику O(NM).</div><div>Обозначим за S(i, j) - подстроку строки S с i-ого по j-ый символ.</div><div>Введем функцию F(x, y) - сколько минимум действий надо выполнить, чтобы из подстроки A(x, N - 1) получить подстроку B(y, M - 1) (индексы символов нумеруются с нуля). Тогда значание F(x, y) это минимум из:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>F(x + 1, y + 1), при x < N, y < M и A[x] = B[x]</i></div></div><div><div><i>F(x + 1, y + 1) + 1, при x < N, y < M</i></div></div><div><div><i>F(x + 1, y), при x < N</i></div></div><div><div><i>F(x, y + 1), при y < M</i></div></div></blockquote><div><div>Очевидно, что F(N, M) равно нулю.</div><div>Если при обработке очередного перехода не только обновлять значение функции, но и запоминать тип перехода, то по окончании подсчета функции F(0, 0) можно будет восстановить набор необходимых операций для превращения строки A в строку B. Ну а само значение F(0, 0) и будет искомым ответом.</div><div><br /></div><div><b>Задача E. Принцип домино</b></div><div>Задача вполне может иметь множество решений, но в данном разборе будет рассказано одно из наиболее тривиальных.</div><div>Для начала отсортируем все доминошки по координате x слева направо, запомнив изначальную нумерацию. Эта нумерация потребуется только для вывода ответа в правильном порядке. Далее нужно сформулировать несколько тривиальных утверждений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Если толкнуть какую-либо доминошку вправо, то среди упавших доминошек все (кроме самой доминошки) будут находиться справа от той, что толкнули.</i></div></div><div><div><i>2) Если какая-либо доминошка упала, то упали и все доминошки, которые находятся левее этой, но не левее той, что изначально толкнули.</i></div></div><div><div><i>3) Для каждой доминошки можно определить номер наиболее правой доминошки такой, что она упадет, если толкнуть данную.</i></div></div></blockquote><div><div>Обозначим за F(i) номер наиболее правой доминошки, которая упадет, если толкнуть i-ую доминошку. Сама по себе i-ая доминошка может не упасть на F(i)-ую, но из-за "принципа домино" F(i)-ая все же упадет. Если доминошка при падении вообще не задевает никакую другую доминошку, то F(i) = i. Очевидно, что такое равенство выполняется для самой правой доминошки. Для остальных доминошек можно найти значение F(i) с помощью уже найденных F(j), где j > i.</div><div>Для каждой доминошки с номером i можно найти такую доминошку с номером j, что при падении i-ая повалит j-ую (непосредственно), и такое j максимально. То есть найти самую правую из доминошек, которую повалит непосредственно i-ая. Далее F(i) = max(F(k)), где k принимает значения на интервале [i + 1, j].</div><div>Реализация решения с асимптотикой O(N<sup>2</sup>) точно не влезет в ограничения по времени. Поэтому необходимо написать решение как минимум за O(NlogN), для чего достаточно воспользоваться структурой данных типа дерева интервалов. Короче говоря, решить задачу Range Maximum Query.</div></div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1558-1147\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1558\",\n blogEntryId: \"1147\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+%2352\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round #52</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80+%D0%B7%D0%B0%D0%B4%D0%B0%D1%87\" class=\"tag notice\" style=\"text-decoration: none;\">разбор задач</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+18</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/pkhaustov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/pkhaustov\">\n pkhaustov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1147#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1147#comments\">\n 7\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1157\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (7)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"503605\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/StayFocus\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/StayFocus\" title=\"Expert StayFocus\" class=\"rated-user user-blue\">StayFocus</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Apr/02/2019 17:19\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-503605\" href=\"?#comment-503605\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"503605\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"870984\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-503605\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>How I use the segment tree to solve problem E ???</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-503605 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-503605 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-503605\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"648445\" commentParentId=\"503605\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/lucifer1004\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1200541/avatar/407a3847bec8a7ec.jpg'/> </a>\n <div><a href=\"/profile/lucifer1004\" title=\"Master lucifer1004\" class=\"rated-user user-orange\">lucifer1004</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jun/23/2020 16:53\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-648445\" href=\"?#comment-648445\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-503605\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"648445\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1200541\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-648445\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>You just need to implement a segment tree which supports single assignment and range minimum query. Since there is no range modification, no lazy propagation is needed, and the segment tree implementation is very simple.</p><p>For the other part, you can just refer to the tutorial.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-648445 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-648445 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-648445\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"727707\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/proudnerd99\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1648278/avatar/375c144d797bf903.jpg'/> </a>\n <div><a href=\"/profile/proudnerd99\" title=\"Expert proudnerd99\" class=\"rated-user user-blue\">proudnerd99</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Nov/30/2020 16:51\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-727707\" href=\"?#comment-727707\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"727707\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"727707\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1648278\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-727707\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>For those of us who don't understand russian, if you are looking for a solution of D, then refer <a href=\"http://www.geeksforgeeks.org/edit-distance-dp-5/\">here:</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-727707 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-727707 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-727707\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"930877\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jul/12/2022 19:19\">15 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-930877\" href=\"?#comment-930877\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"930877\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-930877\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>E Problem can actually be written in a much easier manner(at least I think so :D). You can use dynamic programming. let us create an array dp initialized with 1-s, which will contain how many dominoes can i-th domino flip. we also use another array where on i-th index is written x, which is index of a domino which will not fall if you trip i-th domino. lets call domino with index x barrier of i-th domino. first you sort the pairs by coordinates. Then you go from end to beginning and implement logic:</p><p>1) if i-th domino can cause i+1 to fall, you do dp[i] += dp[i+1]. after this you check if i-th domino can reach i+1-th domino's barrier, if yes dp[i] += dp[x] and then you check x-th domino's barrier and so on. when you find i-th domino's barrier you save it in the second array. we can see that now barrier can only be i-th domino or its barrier(or everything else on its right), so after next iterations we wont have to check dominoes in between. 2) if i-th domino can't flip domino on its right we just save i+1 as i-th domino's barrier.</p><p>sorting will take O(nlogn) and the solution with dp O(n).</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-930877 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-930877 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-930877\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"956835\" commentParentId=\"930877\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/ISeeDS-V2.0\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/ISeeDS-V2.0\" title=\"Specialist ISeeDS-V2.0\" class=\"rated-user user-cyan\">ISeeDS-V2.0</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Sep/27/2022 15:41\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-956835\" href=\"?#comment-956835\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-930877\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"956835\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"2471287\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-956835\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>could you show insert a code link please?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-956835 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-956835 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-956835\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"963107\" commentParentId=\"956835\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/14/2022 16:45\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-963107\" href=\"?#comment-963107\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-956835\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"963107\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-963107\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Here you go: <a href=\"https://github.com/datobena/Algorithms/blob/master/codeforces/56E.cpp\">Code</a>.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-963107 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-963107 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-963107\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"1054419\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/gaurav_436310\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1962290/avatar/cc0070bed7de61db.jpg'/> </a>\n <div><a href=\"/profile/gaurav_436310\" title=\"Newbie gaurav_436310\" class=\"rated-user user-gray\">gaurav_436310</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Aug/02/2023 14:03\">2 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-1054419\" href=\"?#comment-1054419\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"1054419\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1962290\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-1054419\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Where can I find the English version of this editorial?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-1054419 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-1054419 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-1054419\">\r\n </ul>\r\n</div>\r\n 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Changing a String"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Changing a String</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>There is a string <span class=\"tex-span\"><i>s</i></span>, consisting of capital Latin letters. Let's denote its current length as <span class=\"tex-span\">|<i>s</i>|</span>. During one move it is allowed to apply one of the following operations to it: </p><ul> <li> <span class=\"tex-font-style-tt\">INSERT</span> <span class=\"tex-span\"><i>pos</i></span> <span class=\"tex-span\"><i>ch</i></span> — insert a letter <span class=\"tex-span\"><i>ch</i></span> in the string <span class=\"tex-span\"><i>s</i></span> in the position <span class=\"tex-span\"><i>pos</i></span> (<span class=\"tex-span\">1 ≤ <i>pos</i> ≤ |<i>s</i>| + 1, <i>A</i> ≤ <i>ch</i> ≤ <i>Z</i></span>). The letter <span class=\"tex-span\"><i>ch</i></span> becomes the <span class=\"tex-span\"><i>pos</i></span>-th symbol of the string <span class=\"tex-span\"><i>s</i></span>, at that the letters shift aside and the length of the string increases by 1. </li><li> <span class=\"tex-font-style-tt\">DELETE</span> <span class=\"tex-span\"><i>pos</i></span> — delete a character number <span class=\"tex-span\"><i>pos</i></span> (<span class=\"tex-span\">1 ≤ <i>pos</i> ≤ |<i>s</i>|</span>) from the string <span class=\"tex-span\"><i>s</i></span>. At that the letters shift together and the length of the string decreases by 1. </li><li> <span class=\"tex-font-style-tt\">REPLACE</span> <span class=\"tex-span\"><i>pos</i></span> <span class=\"tex-span\"><i>ch</i></span> — the letter in the position <span class=\"tex-span\"><i>pos</i></span> of the line <span class=\"tex-span\"><i>s</i></span> is replaced by <span class=\"tex-span\"><i>ch</i></span> (<span class=\"tex-span\">1 ≤ <i>pos</i> ≤ |<i>s</i>|, <i>A</i> ≤ <i>ch</i> ≤ <i>Z</i></span>). At that the length of the string does not change. </li></ul><p>Your task is to find in which minimal number of moves one can get a <span class=\"tex-span\"><i>t</i></span> string from an <span class=\"tex-span\"><i>s</i></span> string. You should also find the sequence of actions leading to the required results.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains <span class=\"tex-span\"><i>s</i></span>, the second line contains <span class=\"tex-span\"><i>t</i></span>. The lines consist only of capital Latin letters, their lengths are positive numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line print the number of moves <span class=\"tex-span\"><i>k</i></span> in the given sequence of operations. The number should be the minimal possible one. Then print <span class=\"tex-span\"><i>k</i></span> lines containing one operation each. Print the operations in the format, described above. If there are several solutions, print any of them.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>ABA<br/>ABBBA<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br/>INSERT 3 B<br/>INSERT 4 B<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>ACCEPTED<br/>WRONGANSWER<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>10<br/>REPLACE 1 W<br/>REPLACE 2 R<br/>REPLACE 3 O<br/>REPLACE 4 N<br/>REPLACE 5 G<br/>REPLACE 6 A<br/>INSERT 7 N<br/>INSERT 8 S<br/>INSERT 9 W<br/>REPLACE 11 R<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"f8dd8198e367a5185a477c2fb459ceb1\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"0e30376a767efc57081ad269a3df436a8c3d78a2\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Changing a String</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>There is a string <span class=\"tex-span\"><i>s</i></span>, consisting of capital Latin letters. Let's denote its current length as <span class=\"tex-span\">|<i>s</i>|</span>. During one move it is allowed to apply one of the following operations to it: </p><ul> <li> <span class=\"tex-font-style-tt\">INSERT</span> <span class=\"tex-span\"><i>pos</i></span> <span class=\"tex-span\"><i>ch</i></span> — insert a letter <span class=\"tex-span\"><i>ch</i></span> in the string <span class=\"tex-span\"><i>s</i></span> in the position <span class=\"tex-span\"><i>pos</i></span> (<span class=\"tex-span\">1 ≤ <i>pos</i> ≤ |<i>s</i>| + 1, <i>A</i> ≤ <i>ch</i> ≤ <i>Z</i></span>). The letter <span class=\"tex-span\"><i>ch</i></span> becomes the <span class=\"tex-span\"><i>pos</i></span>-th symbol of the string <span class=\"tex-span\"><i>s</i></span>, at that the letters shift aside and the length of the string increases by 1. </li><li> <span class=\"tex-font-style-tt\">DELETE</span> <span class=\"tex-span\"><i>pos</i></span> — delete a character number <span class=\"tex-span\"><i>pos</i></span> (<span class=\"tex-span\">1 ≤ <i>pos</i> ≤ |<i>s</i>|</span>) from the string <span class=\"tex-span\"><i>s</i></span>. At that the letters shift together and the length of the string decreases by 1. </li><li> <span class=\"tex-font-style-tt\">REPLACE</span> <span class=\"tex-span\"><i>pos</i></span> <span class=\"tex-span\"><i>ch</i></span> — the letter in the position <span class=\"tex-span\"><i>pos</i></span> of the line <span class=\"tex-span\"><i>s</i></span> is replaced by <span class=\"tex-span\"><i>ch</i></span> (<span class=\"tex-span\">1 ≤ <i>pos</i> ≤ |<i>s</i>|, <i>A</i> ≤ <i>ch</i> ≤ <i>Z</i></span>). At that the length of the string does not change. </li></ul><p>Your task is to find in which minimal number of moves one can get a <span class=\"tex-span\"><i>t</i></span> string from an <span class=\"tex-span\"><i>s</i></span> string. You should also find the sequence of actions leading to the required results.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains <span class=\"tex-span\"><i>s</i></span>, the second line contains <span class=\"tex-span\"><i>t</i></span>. The lines consist only of capital Latin letters, their lengths are positive numbers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\">1000</span>.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>In the first line print the number of moves <span class=\"tex-span\"><i>k</i></span> in the given sequence of operations. The number should be the minimal possible one. Then print <span class=\"tex-span\"><i>k</i></span> lines containing one operation each. Print the operations in the format, described above. If there are several solutions, print any of them.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>ABA<br />ABBBA<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2<br />INSERT 3 B<br />INSERT 4 B<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>ACCEPTED<br />WRONGANSWER<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>10<br />REPLACE 1 W<br />REPLACE 2 R<br />REPLACE 3 O<br />REPLACE 4 N<br />REPLACE 5 G<br />REPLACE 6 A<br />INSERT 7 N<br />INSERT 8 S<br />INSERT 9 W<br />REPLACE 11 R<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:49</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1ad8da0aaf90aa865343cab51d7160ca'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div 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class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New 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title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/pkhaustov\">pkhaustov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/pkhaustov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/pkhaustov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/pkhaustov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/pkhaustov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/pkhaustov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/pkhaustov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/pkhaustov\" style=\"text-decoration:none;color:black !important;\">pkhaustov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1147\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1147\"> CodeForces Beta Round #52 :: Разбор задач\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/pkhaustov\" title=\"Master pkhaustov\" class=\"rated-user user-orange\">pkhaustov</a>,\r\n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Задача А. Бар</b></div><div>Ответом на задачу является количество посетителей, которые удовлетворяют одному из предложенных ограничений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Указан возраст посетителя и он меньше 18 лет</i></div></div><div><div><i>2) Указан напиток посетителя и он является алкогольным</i></div></div></blockquote><div><div>Далее остается аккуратная реализация.</div><div><br /></div><div><b>Задача B. Испорченная перестановка</b></div><div>Задача имеет множество решений. В разборе будет расказанно решение с асимптотикой O(N), где N - количество элементов последовательности.</div><div>Найдем такое наименьшее i, такое что A<sub>i</sub> не равно i (элементы нумеруются с единицы). Если такого i не существует, то все числа стоят на своих местах и, соответственно, ответом являются два нуля. Иначе, предполагаем, что ответом являются числа i и A<sub>i</sub> (мы можем быть точно уверены, что i < A<sub>i</sub>). Переворачиваем подпоследовательность элементов с i-ого по A<sub>i</sub>-ый и проверяем всю полученную последовательность на то, везде ли A<sub>i</sub> равно i. Если да, то ответом является пара (i, A<sub>i</sub>), иначе ответ - два нуля.</div><div><br /></div><div><b>Задача C. Почта в корпорации</b></div><div>Для решения задачи вполне подходит решение за O(N<sup>2</sup>L), где N - количество людей в иерархии, а L - средняя длина имени сотрудника. То есть сравнение строк можно выполнять без использования хэш-функции.</div><div>Первая часть решения - аккуратная реализация примитивного парсинга строки. Наиболее простой способ - рекурсивная функция, которая читает сначала имя сотрудника, а потом и всех его подчиненных до тех пор, пока не достигнет точки. Далее потребуется хранить в памяти дерево из N вершин. Хранение дерева можно организовать как с помощью динамической памяти, так и простой матрицей смежности. Далее можно просто для каждой вершины запустить обход в глубину из нее и посмотреть скольким вершинам в этом поддереве сопоставлено такое же имя. Стоит обратить внимание на то, что сама вершина, из которой изначально запускается обход в глубину, не должна быть посчитана в ответ.</div><div>Такое решение можно улучшить до сложности O(NlogN), используя хэширование и более сложные структуры данных (например map). При данных ограничениях это было бы пустой тратой времени. Даже грубой оценки N < 500 достаточно, чтобы решение уложилось в time limit.</div><div><br /></div><div><b>Задача D. Получаем строку</b></div><div>Наиболее простым решением этой задачи является решение с использованием динамического программирования. Обозначим первую строку за A, а вторую за B. Длина первой строки равна N, а второй - M. Тогда решение имеет асимптотику O(NM).</div><div>Обозначим за S(i, j) - подстроку строки S с i-ого по j-ый символ.</div><div>Введем функцию F(x, y) - сколько минимум действий надо выполнить, чтобы из подстроки A(x, N - 1) получить подстроку B(y, M - 1) (индексы символов нумеруются с нуля). Тогда значание F(x, y) это минимум из:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>F(x + 1, y + 1), при x < N, y < M и A[x] = B[x]</i></div></div><div><div><i>F(x + 1, y + 1) + 1, при x < N, y < M</i></div></div><div><div><i>F(x + 1, y), при x < N</i></div></div><div><div><i>F(x, y + 1), при y < M</i></div></div></blockquote><div><div>Очевидно, что F(N, M) равно нулю.</div><div>Если при обработке очередного перехода не только обновлять значение функции, но и запоминать тип перехода, то по окончании подсчета функции F(0, 0) можно будет восстановить набор необходимых операций для превращения строки A в строку B. Ну а само значение F(0, 0) и будет искомым ответом.</div><div><br /></div><div><b>Задача E. Принцип домино</b></div><div>Задача вполне может иметь множество решений, но в данном разборе будет рассказано одно из наиболее тривиальных.</div><div>Для начала отсортируем все доминошки по координате x слева направо, запомнив изначальную нумерацию. Эта нумерация потребуется только для вывода ответа в правильном порядке. Далее нужно сформулировать несколько тривиальных утверждений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Если толкнуть какую-либо доминошку вправо, то среди упавших доминошек все (кроме самой доминошки) будут находиться справа от той, что толкнули.</i></div></div><div><div><i>2) Если какая-либо доминошка упала, то упали и все доминошки, которые находятся левее этой, но не левее той, что изначально толкнули.</i></div></div><div><div><i>3) Для каждой доминошки можно определить номер наиболее правой доминошки такой, что она упадет, если толкнуть данную.</i></div></div></blockquote><div><div>Обозначим за F(i) номер наиболее правой доминошки, которая упадет, если толкнуть i-ую доминошку. Сама по себе i-ая доминошка может не упасть на F(i)-ую, но из-за "принципа домино" F(i)-ая все же упадет. Если доминошка при падении вообще не задевает никакую другую доминошку, то F(i) = i. Очевидно, что такое равенство выполняется для самой правой доминошки. Для остальных доминошек можно найти значение F(i) с помощью уже найденных F(j), где j > i.</div><div>Для каждой доминошки с номером i можно найти такую доминошку с номером j, что при падении i-ая повалит j-ую (непосредственно), и такое j максимально. То есть найти самую правую из доминошек, которую повалит непосредственно i-ая. Далее F(i) = max(F(k)), где k принимает значения на интервале [i + 1, j].</div><div>Реализация решения с асимптотикой O(N<sup>2</sup>) точно не влезет в ограничения по времени. Поэтому необходимо написать решение как минимум за O(NlogN), для чего достаточно воспользоваться структурой данных типа дерева интервалов. Короче говоря, решить задачу Range Maximum Query.</div></div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1558-1147\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1558\",\n blogEntryId: \"1147\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+%2352\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round #52</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80+%D0%B7%D0%B0%D0%B4%D0%B0%D1%87\" class=\"tag notice\" style=\"text-decoration: none;\">разбор задач</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+18</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/pkhaustov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/pkhaustov\">\n pkhaustov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1147#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1147#comments\">\n 7\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1157\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (7)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"503605\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/StayFocus\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/StayFocus\" title=\"Expert StayFocus\" class=\"rated-user user-blue\">StayFocus</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Apr/02/2019 17:19\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-503605\" href=\"?#comment-503605\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"503605\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"870984\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-503605\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>How I use the segment tree to solve problem E ???</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-503605 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-503605 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-503605\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"648445\" commentParentId=\"503605\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/lucifer1004\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1200541/avatar/407a3847bec8a7ec.jpg'/> </a>\n <div><a href=\"/profile/lucifer1004\" title=\"Master lucifer1004\" class=\"rated-user user-orange\">lucifer1004</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jun/23/2020 16:53\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-648445\" href=\"?#comment-648445\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-503605\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"648445\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1200541\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-648445\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>You just need to implement a segment tree which supports single assignment and range minimum query. Since there is no range modification, no lazy propagation is needed, and the segment tree implementation is very simple.</p><p>For the other part, you can just refer to the tutorial.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-648445 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-648445 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-648445\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"727707\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/proudnerd99\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1648278/avatar/375c144d797bf903.jpg'/> </a>\n <div><a href=\"/profile/proudnerd99\" title=\"Expert proudnerd99\" class=\"rated-user user-blue\">proudnerd99</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Nov/30/2020 16:51\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-727707\" href=\"?#comment-727707\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"727707\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"727707\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1648278\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-727707\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>For those of us who don't understand russian, if you are looking for a solution of D, then refer <a href=\"http://www.geeksforgeeks.org/edit-distance-dp-5/\">here:</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-727707 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-727707 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-727707\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"930877\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jul/12/2022 19:19\">15 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-930877\" href=\"?#comment-930877\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"930877\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-930877\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>E Problem can actually be written in a much easier manner(at least I think so :D). You can use dynamic programming. let us create an array dp initialized with 1-s, which will contain how many dominoes can i-th domino flip. we also use another array where on i-th index is written x, which is index of a domino which will not fall if you trip i-th domino. lets call domino with index x barrier of i-th domino. first you sort the pairs by coordinates. Then you go from end to beginning and implement logic:</p><p>1) if i-th domino can cause i+1 to fall, you do dp[i] += dp[i+1]. after this you check if i-th domino can reach i+1-th domino's barrier, if yes dp[i] += dp[x] and then you check x-th domino's barrier and so on. when you find i-th domino's barrier you save it in the second array. we can see that now barrier can only be i-th domino or its barrier(or everything else on its right), so after next iterations we wont have to check dominoes in between. 2) if i-th domino can't flip domino on its right we just save i+1 as i-th domino's barrier.</p><p>sorting will take O(nlogn) and the solution with dp O(n).</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-930877 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-930877 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-930877\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"956835\" commentParentId=\"930877\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/ISeeDS-V2.0\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/ISeeDS-V2.0\" title=\"Specialist ISeeDS-V2.0\" class=\"rated-user user-cyan\">ISeeDS-V2.0</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Sep/27/2022 15:41\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-956835\" href=\"?#comment-956835\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-930877\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"956835\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"2471287\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-956835\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>could you show insert a code link please?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-956835 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-956835 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-956835\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"963107\" commentParentId=\"956835\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/14/2022 16:45\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-963107\" href=\"?#comment-963107\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-956835\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"963107\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-963107\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Here you go: <a href=\"https://github.com/datobena/Algorithms/blob/master/codeforces/56E.cpp\">Code</a>.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-963107 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-963107 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-963107\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"1054419\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/gaurav_436310\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1962290/avatar/cc0070bed7de61db.jpg'/> </a>\n <div><a href=\"/profile/gaurav_436310\" title=\"Newbie gaurav_436310\" class=\"rated-user user-gray\">gaurav_436310</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Aug/02/2023 14:03\">2 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-1054419\" href=\"?#comment-1054419\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"1054419\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1962290\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-1054419\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Where can I find the English version of this editorial?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-1054419 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-1054419 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-1054419\">\r\n </ul>\r\n</div>\r\n 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Domino Principle"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Domino Principle</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya is interested in arranging dominoes. He is fed up with common dominoes and he uses the dominoes of different heights. He put <span class=\"tex-span\"><i>n</i></span> dominoes on the table along one axis, going from left to right. Every domino stands perpendicular to that axis so that the axis passes through the center of its base. The <span class=\"tex-span\"><i>i</i></span>-th domino has the coordinate <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span> and the height <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span>. Now Vasya wants to learn for every domino, how many dominoes will fall if he pushes it to the right. Help him do that. </p><p>Consider that a domino falls if it is touched strictly above the base. In other words, the fall of the domino with the initial coordinate <span class=\"tex-span\"><i>x</i></span> and height <span class=\"tex-span\"><i>h</i></span> leads to the fall of all dominoes on the segment <span class=\"tex-span\">[<i>x</i> + 1, <i>x</i> + <i>h</i> - 1]</span>.</p><center><img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/6be8a0bab99fd497cc3eba6b86f7f0cf07804cea.png\" style=\"max-width: 100.0%;max-height: 100.0%;\"/></center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">5</sup></span>) which is the number of dominoes. Then follow <span class=\"tex-span\"><i>n</i></span> lines containing two integers <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 10<sup class=\"upper-index\">8</sup> ≤ <i>x</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">8</sup>, 2 ≤ <i>h</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">8</sup></span>) each, which are the coordinate and height of every domino. No two dominoes stand on one point.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print <span class=\"tex-span\"><i>n</i></span> space-separated numbers <span class=\"tex-span\"><i>z</i><sub class=\"lower-index\"><i>i</i></sub></span> — the number of dominoes that will fall if Vasya pushes the <span class=\"tex-span\"><i>i</i></span>-th domino to the right (including the domino itself).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>16 5<br/>20 5<br/>10 10<br/>18 2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 1 4 1 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br/>0 10<br/>1 5<br/>9 10<br/>15 10<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4 1 2 1 </pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"232a351997898fd846b7234e918e5622\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"0e30376a767efc57081ad269a3df436a8c3d78a2\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"E\" data-uuid=\"ps_7b2fbe85889bbb420c2b94c86cbbb8f6ba8bee6e\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Domino Principle</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya is interested in arranging dominoes. He is fed up with common dominoes and he uses the dominoes of different heights. He put <span class=\"tex-span\"><i>n</i></span> dominoes on the table along one axis, going from left to right. Every domino stands perpendicular to that axis so that the axis passes through the center of its base. The <span class=\"tex-span\"><i>i</i></span>-th domino has the coordinate <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span> and the height <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span>. Now Vasya wants to learn for every domino, how many dominoes will fall if he pushes it to the right. Help him do that. </p><p>Consider that a domino falls if it is touched strictly above the base. In other words, the fall of the domino with the initial coordinate <span class=\"tex-span\"><i>x</i></span> and height <span class=\"tex-span\"><i>h</i></span> leads to the fall of all dominoes on the segment <span class=\"tex-span\">[<i>x</i> + 1, <i>x</i> + <i>h</i> - 1]</span>.</p><center><img class=\"tex-graphics\" src=\"https://espresso.codeforces.com/6be8a0bab99fd497cc3eba6b86f7f0cf07804cea.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /></center></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains integer <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">5</sup></span>) which is the number of dominoes. Then follow <span class=\"tex-span\"><i>n</i></span> lines containing two integers <span class=\"tex-span\"><i>x</i><sub class=\"lower-index\"><i>i</i></sub></span> and <span class=\"tex-span\"><i>h</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\"> - 10<sup class=\"upper-index\">8</sup> ≤ <i>x</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">8</sup>, 2 ≤ <i>h</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 10<sup class=\"upper-index\">8</sup></span>) each, which are the coordinate and height of every domino. No two dominoes stand on one point.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>Print <span class=\"tex-span\"><i>n</i></span> space-separated numbers <span class=\"tex-span\"><i>z</i><sub class=\"lower-index\"><i>i</i></sub></span> — the number of dominoes that will fall if Vasya pushes the <span class=\"tex-span\"><i>i</i></span>-th domino to the right (including the domino itself).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />16 5<br />20 5<br />10 10<br />18 2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>3 1 4 1 </pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>4<br />0 10<br />1 5<br />9 10<br />15 10<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4 1 2 1 </pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:49</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='1ad8da0aaf90aa865343cab51d7160ca'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a 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style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/119880\">It's Happening! Meta Hacker Cup 2023 Schedule</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/DaviddeGea1\" title=\"Expert DaviddeGea1\" class=\"rated-user user-blue\">DaviddeGea1</a> →\r\n <a href=\"/blog/entry/70917\">Number of ways of dividing an array into 2 parts such that sum of each part is > k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a> →\r\n <a href=\"/blog/entry/74245\">Questions and doubts regarding Aliens DP trick</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/cgy4ever\" title=\"International Grandmaster cgy4ever\" class=\"rated-user user-red\">cgy4ever</a> →\r\n <a href=\"/blog/entry/8192\">Codeforces Round #190 — Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/hocky\" title=\"Candidate Master hocky\" class=\"rated-user user-violet\">hocky</a> →\r\n <a href=\"/blog/entry/95323\">FBHC wuining uw Day? Incwease uw stacc size! (ㅅ´ ˘ `)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/liouzhou_101\" title=\"International Master liouzhou_101\" class=\"rated-user user-orange\">liouzhou_101</a> →\r\n <a href=\"/blog/entry/87598\">Editorial of Codeforces Round #700</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div 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class=\"rated-user user-blue\">ankancool</a> →\r\n <a href=\"/blog/entry/121136\">Invitation to AstroByte 2023</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/GeZhiyuan\" title=\"Grandmaster GeZhiyuan\" class=\"rated-user user-red\">GeZhiyuan</a> →\r\n <a href=\"/blog/entry/120943\">Codeforces Round 901 (Div. 1, Div. 2) Editorial</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a> →\r\n <a href=\"/blog/entry/120772\">PSA: Increase your stack size before the Meta Hacker Cup, here's how</a>\r\n <img alt=\"New 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title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Bn00b\" title=\"Newbie Bn00b\" class=\"rated-user user-gray\">Bn00b</a> →\r\n <a href=\"/blog/entry/98820\">[FEATURE REQUEST : ATCODER] TOPICS TAGS AND SORTING BY SOLVE COUNT</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n <img alt=\"Necropost\" title=\"Necropost\" src=\"//codeforces.org/s/81027/images/icons/hourglass.png\" style=\"vertical-align:middle; position: relative; top: 1px;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a> →\r\n <a href=\"/blog/entry/121163\">AtCoder Regular Contest 166 Announcement</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/windva\" title=\"Grandmaster windva\" class=\"rated-user user-red\">windva</a> →\r\n <a href=\"/blog/entry/120644\">Codeforces Round 899 (Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Misa-Misa\" title=\"Expert Misa-Misa\" class=\"rated-user user-blue\">Misa-Misa</a> →\r\n <a href=\"/blog/entry/121157\">Someone please help me understand this.</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/shivam565\" title=\"Specialist shivam565\" class=\"rated-user user-cyan\">shivam565</a> →\r\n <a href=\"/blog/entry/108348\">Total number of subarrays with sum atmost k</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n </ul>\r\n </div>\r\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/recent-actions\">Detailed →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n</div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li><a\r\n href=\"/profile/pkhaustov\">pkhaustov</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/pkhaustov\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/pkhaustov\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/pkhaustov\">Submissions</a></li>\r\n <li><a\r\n href=\"/groups/with/pkhaustov\">Groups</a></li>\r\n <li><a\r\n href=\"/contests/with/pkhaustov\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/pkhaustov\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/pkhaustov\" style=\"text-decoration:none;color:black !important;\">pkhaustov's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1147\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1147\"> CodeForces Beta Round #52 :: Разбор задач\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/pkhaustov\" title=\"Master pkhaustov\" class=\"rated-user user-orange\">pkhaustov</a>,\r\n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>,\r\n \r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/ru.png\" alt=\"In Russian\" title=\"In Russian\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div><div><b>Задача А. Бар</b></div><div>Ответом на задачу является количество посетителей, которые удовлетворяют одному из предложенных ограничений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Указан возраст посетителя и он меньше 18 лет</i></div></div><div><div><i>2) Указан напиток посетителя и он является алкогольным</i></div></div></blockquote><div><div>Далее остается аккуратная реализация.</div><div><br /></div><div><b>Задача B. Испорченная перестановка</b></div><div>Задача имеет множество решений. В разборе будет расказанно решение с асимптотикой O(N), где N - количество элементов последовательности.</div><div>Найдем такое наименьшее i, такое что A<sub>i</sub> не равно i (элементы нумеруются с единицы). Если такого i не существует, то все числа стоят на своих местах и, соответственно, ответом являются два нуля. Иначе, предполагаем, что ответом являются числа i и A<sub>i</sub> (мы можем быть точно уверены, что i < A<sub>i</sub>). Переворачиваем подпоследовательность элементов с i-ого по A<sub>i</sub>-ый и проверяем всю полученную последовательность на то, везде ли A<sub>i</sub> равно i. Если да, то ответом является пара (i, A<sub>i</sub>), иначе ответ - два нуля.</div><div><br /></div><div><b>Задача C. Почта в корпорации</b></div><div>Для решения задачи вполне подходит решение за O(N<sup>2</sup>L), где N - количество людей в иерархии, а L - средняя длина имени сотрудника. То есть сравнение строк можно выполнять без использования хэш-функции.</div><div>Первая часть решения - аккуратная реализация примитивного парсинга строки. Наиболее простой способ - рекурсивная функция, которая читает сначала имя сотрудника, а потом и всех его подчиненных до тех пор, пока не достигнет точки. Далее потребуется хранить в памяти дерево из N вершин. Хранение дерева можно организовать как с помощью динамической памяти, так и простой матрицей смежности. Далее можно просто для каждой вершины запустить обход в глубину из нее и посмотреть скольким вершинам в этом поддереве сопоставлено такое же имя. Стоит обратить внимание на то, что сама вершина, из которой изначально запускается обход в глубину, не должна быть посчитана в ответ.</div><div>Такое решение можно улучшить до сложности O(NlogN), используя хэширование и более сложные структуры данных (например map). При данных ограничениях это было бы пустой тратой времени. Даже грубой оценки N < 500 достаточно, чтобы решение уложилось в time limit.</div><div><br /></div><div><b>Задача D. Получаем строку</b></div><div>Наиболее простым решением этой задачи является решение с использованием динамического программирования. Обозначим первую строку за A, а вторую за B. Длина первой строки равна N, а второй - M. Тогда решение имеет асимптотику O(NM).</div><div>Обозначим за S(i, j) - подстроку строки S с i-ого по j-ый символ.</div><div>Введем функцию F(x, y) - сколько минимум действий надо выполнить, чтобы из подстроки A(x, N - 1) получить подстроку B(y, M - 1) (индексы символов нумеруются с нуля). Тогда значание F(x, y) это минимум из:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>F(x + 1, y + 1), при x < N, y < M и A[x] = B[x]</i></div></div><div><div><i>F(x + 1, y + 1) + 1, при x < N, y < M</i></div></div><div><div><i>F(x + 1, y), при x < N</i></div></div><div><div><i>F(x, y + 1), при y < M</i></div></div></blockquote><div><div>Очевидно, что F(N, M) равно нулю.</div><div>Если при обработке очередного перехода не только обновлять значение функции, но и запоминать тип перехода, то по окончании подсчета функции F(0, 0) можно будет восстановить набор необходимых операций для превращения строки A в строку B. Ну а само значение F(0, 0) и будет искомым ответом.</div><div><br /></div><div><b>Задача E. Принцип домино</b></div><div>Задача вполне может иметь множество решений, но в данном разборе будет рассказано одно из наиболее тривиальных.</div><div>Для начала отсортируем все доминошки по координате x слева направо, запомнив изначальную нумерацию. Эта нумерация потребуется только для вывода ответа в правильном порядке. Далее нужно сформулировать несколько тривиальных утверждений:</div></div><blockquote style=\"margin: 0 0 0 40.0px;border: none;padding: 0.0px;\"><div><div><i>1) Если толкнуть какую-либо доминошку вправо, то среди упавших доминошек все (кроме самой доминошки) будут находиться справа от той, что толкнули.</i></div></div><div><div><i>2) Если какая-либо доминошка упала, то упали и все доминошки, которые находятся левее этой, но не левее той, что изначально толкнули.</i></div></div><div><div><i>3) Для каждой доминошки можно определить номер наиболее правой доминошки такой, что она упадет, если толкнуть данную.</i></div></div></blockquote><div><div>Обозначим за F(i) номер наиболее правой доминошки, которая упадет, если толкнуть i-ую доминошку. Сама по себе i-ая доминошка может не упасть на F(i)-ую, но из-за "принципа домино" F(i)-ая все же упадет. Если доминошка при падении вообще не задевает никакую другую доминошку, то F(i) = i. Очевидно, что такое равенство выполняется для самой правой доминошки. Для остальных доминошек можно найти значение F(i) с помощью уже найденных F(j), где j > i.</div><div>Для каждой доминошки с номером i можно найти такую доминошку с номером j, что при падении i-ая повалит j-ую (непосредственно), и такое j максимально. То есть найти самую правую из доминошек, которую повалит непосредственно i-ая. Далее F(i) = max(F(k)), где k принимает значения на интервале [i + 1, j].</div><div>Реализация решения с асимптотикой O(N<sup>2</sup>) точно не влезет в ограничения по времени. Поэтому необходимо написать решение как минимум за O(NlogN), для чего достаточно воспользоваться структурой данных типа дерева интервалов. Короче говоря, решить задачу Range Maximum Query.</div></div></div>\r\n\r\n </div>\r\n\r\n\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1558-1147\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1558\",\n blogEntryId: \"1147\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+%2352\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round #52</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+%D1%84%D0%BE%D1%80%D0%BC%D0%B0%D1%82\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces формат</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=%D1%80%D0%B0%D0%B7%D0%B1%D0%BE%D1%80+%D0%B7%D0%B0%D0%B4%D0%B0%D1%87\" class=\"tag notice\" style=\"text-decoration: none;\">разбор задач</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+18</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1147\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/pkhaustov\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/pkhaustov\">\n pkhaustov\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/21/2011 23:46\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1147#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1147#comments\">\n 7\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1157\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (7)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"503605\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/StayFocus\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/StayFocus\" title=\"Expert StayFocus\" class=\"rated-user user-blue\">StayFocus</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Apr/02/2019 17:19\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-503605\" href=\"?#comment-503605\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"503605\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"870984\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-503605\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>How I use the segment tree to solve problem E ???</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-503605 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-503605 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-503605\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"648445\" commentParentId=\"503605\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/lucifer1004\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1200541/avatar/407a3847bec8a7ec.jpg'/> </a>\n <div><a href=\"/profile/lucifer1004\" title=\"Master lucifer1004\" class=\"rated-user user-orange\">lucifer1004</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jun/23/2020 16:53\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-648445\" href=\"?#comment-648445\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-503605\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"648445\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1200541\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-648445\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>You just need to implement a segment tree which supports single assignment and range minimum query. Since there is no range modification, no lazy propagation is needed, and the segment tree implementation is very simple.</p><p>For the other part, you can just refer to the tutorial.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-648445 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-648445 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-648445\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"727707\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/proudnerd99\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1648278/avatar/375c144d797bf903.jpg'/> </a>\n <div><a href=\"/profile/proudnerd99\" title=\"Expert proudnerd99\" class=\"rated-user user-blue\">proudnerd99</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Nov/30/2020 16:51\">3 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-727707\" href=\"?#comment-727707\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"727707\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"727707\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1648278\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-727707\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>For those of us who don't understand russian, if you are looking for a solution of D, then refer <a href=\"http://www.geeksforgeeks.org/edit-distance-dp-5/\">here:</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-727707 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-727707 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-727707\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"930877\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jul/12/2022 19:19\">15 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-930877\" href=\"?#comment-930877\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"930877\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-930877\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>E Problem can actually be written in a much easier manner(at least I think so :D). You can use dynamic programming. let us create an array dp initialized with 1-s, which will contain how many dominoes can i-th domino flip. we also use another array where on i-th index is written x, which is index of a domino which will not fall if you trip i-th domino. lets call domino with index x barrier of i-th domino. first you sort the pairs by coordinates. Then you go from end to beginning and implement logic:</p><p>1) if i-th domino can cause i+1 to fall, you do dp[i] += dp[i+1]. after this you check if i-th domino can reach i+1-th domino's barrier, if yes dp[i] += dp[x] and then you check x-th domino's barrier and so on. when you find i-th domino's barrier you save it in the second array. we can see that now barrier can only be i-th domino or its barrier(or everything else on its right), so after next iterations we wont have to check dominoes in between. 2) if i-th domino can't flip domino on its right we just save i+1 as i-th domino's barrier.</p><p>sorting will take O(nlogn) and the solution with dp O(n).</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-930877 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-930877 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-930877\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"956835\" commentParentId=\"930877\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/ISeeDS-V2.0\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/ISeeDS-V2.0\" title=\"Specialist ISeeDS-V2.0\" class=\"rated-user user-cyan\">ISeeDS-V2.0</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Sep/27/2022 15:41\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-956835\" href=\"?#comment-956835\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-930877\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"956835\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"2471287\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-956835\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>could you show insert a code link please?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-956835 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-956835 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-956835\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"963107\" commentParentId=\"956835\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/DBena\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/770609/avatar/c884eedaf62f398e.jpg'/> </a>\n <div><a href=\"/profile/DBena\" title=\"Pupil DBena\" class=\"rated-user user-green\">DBena</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/14/2022 16:45\">12 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-963107\" href=\"?#comment-963107\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-956835\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"963107\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"770609\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-963107\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Here you go: <a href=\"https://github.com/datobena/Algorithms/blob/master/codeforces/56E.cpp\">Code</a>.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-963107 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-963107 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-963107\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"1054419\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/gaurav_436310\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1962290/avatar/cc0070bed7de61db.jpg'/> </a>\n <div><a href=\"/profile/gaurav_436310\" title=\"Newbie gaurav_436310\" class=\"rated-user user-gray\">gaurav_436310</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Aug/02/2023 14:03\">2 months ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-1054419\" href=\"?#comment-1054419\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"1054419\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1962290\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-1054419\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Where can I find the English version of this editorial?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-1054419 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-1054419 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-1054419\">\r\n </ul>\r\n</div>\r\n 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Square Earth?"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Square Earth?</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Meg the Rabbit decided to do something nice, specifically — to determine the shortest distance between two points on the surface of our planet. But Meg... what can you say, she wants everything simple. So, she already regards our planet as a two-dimensional circle. No, wait, it's even worse — as a square of side <span class=\"tex-span\"><i>n</i></span>. Thus, the task has been reduced to finding the shortest path between two dots on a square (the path should go through the square sides). To simplify the task let us consider the vertices of the square to lie at points whose coordinates are: <span class=\"tex-span\">(0, 0)</span>, <span class=\"tex-span\">(<i>n</i>, 0)</span>, <span class=\"tex-span\">(0, <i>n</i>)</span> and <span class=\"tex-span\">(<i>n</i>, <i>n</i>)</span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The single line contains 5 space-separated integers: <span class=\"tex-span\"><i>n</i>, <i>x</i><sub class=\"lower-index\">1</sub>, <i>y</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, <i>y</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 1000, 0 ≤ <i>x</i><sub class=\"lower-index\">1</sub>, <i>y</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, <i>y</i><sub class=\"lower-index\">2</sub> ≤ <i>n</i></span>) which correspondingly represent a side of the square, the coordinates of the first point and the coordinates of the second point. It is guaranteed that the points lie on the sides of the square.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You must print on a single line the shortest distance between the points.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 0 0 1 0<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 0 1 2 1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>100 0 0 100 100<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>200<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"b067e5293158b4f4c701baed933552ce\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"ac67dea8cf3109b0107a111cd3f3e199fc14c4b4\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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\"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_7bdc53e09852df19cd8a5bacb3c6e8805a784b0e\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Square Earth?</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Meg the Rabbit decided to do something nice, specifically — to determine the shortest distance between two points on the surface of our planet. But Meg... what can you say, she wants everything simple. So, she already regards our planet as a two-dimensional circle. No, wait, it's even worse — as a square of side <span class=\"tex-span\"><i>n</i></span>. Thus, the task has been reduced to finding the shortest path between two dots on a square (the path should go through the square sides). To simplify the task let us consider the vertices of the square to lie at points whose coordinates are: <span class=\"tex-span\">(0, 0)</span>, <span class=\"tex-span\">(<i>n</i>, 0)</span>, <span class=\"tex-span\">(0, <i>n</i>)</span> and <span class=\"tex-span\">(<i>n</i>, <i>n</i>)</span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The single line contains 5 space-separated integers: <span class=\"tex-span\"><i>n</i>, <i>x</i><sub class=\"lower-index\">1</sub>, <i>y</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, <i>y</i><sub class=\"lower-index\">2</sub></span> (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 1000, 0 ≤ <i>x</i><sub class=\"lower-index\">1</sub>, <i>y</i><sub class=\"lower-index\">1</sub>, <i>x</i><sub class=\"lower-index\">2</sub>, <i>y</i><sub class=\"lower-index\">2</sub> ≤ <i>n</i></span>) which correspondingly represent a side of the square, the coordinates of the first point and the coordinates of the second point. It is guaranteed that the points lie on the sides of the square.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You must print on a single line the shortest distance between the points.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 0 0 1 0<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>1<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 0 1 2 1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>100 0 0 100 100<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>200<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n <div style=\"text-align:center;\">\r\n <span class='contest-state-phase'>Before contest</span><br/><a href=\"/contests/1876,1877\">Codeforces Round 902 (Div. 2, based on COMPFEST 15 - Final Round)</a><br/><span class='countdown' home='//codeforces.org/s/81027' noRedirection='true' textBeforeRedirect=''>13:56:49</span><br/><a href=\"/contestRegistration/1877\">Register now »</a><div class=\"smaller notice\">*has extra registration<i class=\"icon-question-sign clickable-title\" title=\"If you are late to register in 5 minutes before the start, you can register later during the extra registration. Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='ce6ca9373d76d422a834978ac82e9761'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/nevidomy\">nevidomy</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/nevidomy\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/nevidomy\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/nevidomy\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/nevidomy\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/nevidomy\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/nevidomy\" style=\"text-decoration:none;color:black !important;\">nevidomy's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1171\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1171\"> Codeforces Beta Round #53 [Analysis]\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/nevidomy\" title=\"Candidate Master nevidomy\" class=\"rated-user user-violet\">nevidomy</a>,\r\n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h3></h3><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"verdana, arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem А.</span></font><br /></h3><p style=\"margin-top: 1.0em;margin-right: 0.0px;margin-bottom: 1.0em;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-size: 12.0px;line-height: 20.0px;font-family: Verdana;font-weight: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;line-height: normal;font-size: small;\"></span></font></p><p><font face=\"Arial, sans-serif\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Since the restrictions were not so big you can offer many different solutions. For example, you can construct a graph with N * 4 vertices and use bfs. But there was a faster solution with complexity O(1): enumerate the integer points lying on the square, for example, as is shown below:</span></span><span style=\"font-size: 9.0pt;font-family: Verdana , sans-serif;\"></span></font></p><p style=\"font-family: verdana , arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><img src=\"https://vnevidomy.narod2.ru/images/a-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Then finding the number of a point by its coordinates isn’t difficult. For example if a point has coordinate y == n -> then its position is n + x (if the numeration, is as shown, i.e. starts with zero). It turns out that we have transformed the square into a line with a small complication: cells N * 4 - 1 and 0 are adjacent, so we have not a line but a circle, where for the base points from 0 to 4 * N-1 the distance between the adjacent two points is 1. It is easy to take the difference of indices of the points and find the distance when moving clockwise and counterclockwise: (a-b +4 * n)% (4 * n) and (b - a + 4 * n)% (4 * n), the shortest distance will be the answer.</span></span></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem B</span></h3><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-size: 10.0pt;font-family: Arial , sans-serif;color: black;\">Under the restrictions on the number of requests, you cannot iteratively add staircase. But the problem is simplified by the fact that the number of cells in which it was necessary to know the number of stones was no more than 100. That’s why you can check for each "interesting" cell all the queries and calculate how much each of them adds stones, so the complexity is: O (K * M), which fits within the given 2 seconds well. A faster solution with complexity O(N + M + K) is as follows: we will keep in mind two variables: a – how many items should be added now to the cell, v - how much should change a next step. So problem is to update the value of a and v so that a equaled to the number of stones in the cell after all the operations, and v – to how much a increases during the transition to the next cell. Then the problem will be reduced to that you need to properly update a and v, which is not very difficult to do, for example if there is a request (x, y, z) – then in the cell x you need to add x to a and add 1 to v, since with each next cell the number of stones for some staircase will increase by 1. Similarly, after the cell y is passed you need to subtract 1 from v and pick up from “a” the current number of stones subquery. If you save all such pairs of queries in a single array and it's possible to calculate everything in one cycle.</span></span><span style=\"color: black;\"></span></font></p><p><font face=\"arial\" size=\"2\"></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"arial\" size=\"2\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem C</span></font></font></h3><p style=\"color: black;font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">First, let's count how many there are arrays in which each successive element starting from the second one is no less than the previous one. To do this quickly, let’s take a piece of squared with height of one square and the length of N*2 - 1 square, then select N-1 squares and put crosses in them - let it encode some array, let the number of blank cells from the beginning of the array before the first cross be equal to the number of ones in the array, the number of blank cells from the first cross to the second – to the number of 2 in the array, and so on. It is easy to see that the number of empty cells will be equal to N * 2-1 - (N-1) = N. It turns out that each paper encodes an array which suits us, and moreover all the possible arrays can be encoded using such paper. There is exactly C (N * 2-1, N) different pieces of paper (the binomial coefficient of N * 2-1 to N). This number can be calculated by formula with factorials, the only difficulty is division. Since the module was prime - it was possible to calculate the inverse number in the field for the module and replace division by multiplication. So we get the number of non-decreasing sequences, respectively have the same number of non-increasing, we just need to take away those who were represented in both array sets, but they are just arrays with a similar number like {1,1,1,...,1} or {4,4,...,4,4} just subtract n.</span></span><span style=\"font-size: 9.0pt;font-family: Arial , sans-serif;color: black;\"></span></font></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem D</span></font></h3><p style=\"color: black;font-family: Arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><span><span lang=\"RU\" style=\"font-family: Arial , sans-serif;color: black;\"></span></span></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Let's see, if there is no occupied cells, then it is not difficult to calculate the answer - the answer is a sum of Manhattan distances, taking into account the fact that the Manhattan distance can be divided: first we can calculate the distance of one coordinate and then of another one and then just to sum up, so the answer is not difficult to find. What do we have when there are occupied cells? If the cell from which we seek the distance does not lie on the same horizontal or vertical with occupied cells – then it absolutely does not affect the difficulty of accessing the rest of the cells:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">This happens due to the fact that in each cell from the previous distance front (the distance to the set of cells with maximum distance from the start cell, the fronts form a diamond as you can see in the picture or from the Manhattan distance formula) there are two ways how to get to the cell, we take into account the rule that no two cells can be adjacent (either diagonally or vertically or horizontally), it turns out that such a cell does not interfere with us. But a close look at the picture brings to mind the obvious: it is the cell which is located on the same vertical / horizontal that has only one neighbor from the previous front, let’s see what happens in such case:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-2.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;font-size: small;\">All the cells after occupied one starts "to lag" at 2 in distance, but more importantly, that changed the front! Now (with the upper side of the front) are 2 cells for which the transition from the previous front is unique, and as a consequence there are two cells meeting of which will produce a new segment of a late cells, and the angle of the front will change again. Since we are only interested in one side of its expansion (on the other hand there can not be occupied cells by the condition) so we can assume that it was expand from the start cell:</span><br /></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-3.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">It turns out that you can count how many cells will be "delayed", especially considering that the lag always equals to two. For each direction, you can choose each occupied cell and check in the left and right directions for adjacent cells series, and add delay for interval of free cell before occupied cell (in the current direction). It is possible to calculate such delays with complexity: square of the number of occupied cells (it is not greater than min(N, M)). The rest is details. You need to compute all Manhattan distances, taking into account the existence of occupied cells. To do this, first calculate the sum of distances for an empty field, then for each occupied cell calculate the distance to all the others - subtract it twice, as the extra distance is subtracted for the first time when we got out of this cell and for the second time when takes away from all other cells to the given one. But in this case we will take away twice the distance between two occupied cells - so we’ll have to add them (the complexity is also a square). A total complexity of solution is O (K ^ 2) where K is the number of occupied cells.</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem E</span></font></h3><h3 style=\"font-weight: normal;\"><span style=\"font-weight: normal;\"><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">The task turned out to be very difficult as it was planned. First remove all the deleted cells - let's see how changes the number of accessible cells with the increase of the new moves. First, the changes do not appear stable, but at some point we see a figure which won’t to change the form anymore and will only expand, it is obvious that the figure is two-dimensional, therefore the growth of its “area” is a quadratic function, in fact, a simple check shows that with each new turn the number of cells increases by the number of new cells opened with previous turn + 28, so after a certain point, you can simply take the sum of an arithmetic progression. The case with the deleted cells is similar. In general, there are several possible options - either occupied cells block further penetration of the horse or not, in the first case bfs is simply enough to find solutions, in the second one the story is the same: over time, when the figure "becomes balanced", the number of new opened cells satisfies the same rule "prev +28" . Moreover, because of restrictions of the coordinates of the deleted cells (-10 <= x, y <= 10) this happens fairly quickly. So, use usual bfs to balance figures, and after this use the sum of the arithmetic progression.</span></span><span style=\"color: black;\"></span></font></p></span></h3></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/57\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 53</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-296-1171\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"296\",\n blogEntryId: \"1171\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+53\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 53</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+24</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/nevidomy\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/nevidomy\">\n nevidomy\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1171#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1171#comments\">\n 15\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1181\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (12)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20840\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lyrics\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3858/avatar/29787cdba9b12888.jpg'/> </a>\n <div><a href=\"/profile/lyrics\" title=\"Expert lyrics\" class=\"rated-user user-blue\">lyrics</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 04:43\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20840\" href=\"?#comment-20840\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20840\" revisionCount=\"5\" revision=\"5\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">5</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20840\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"3858\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20840\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">the translation is a bit difficult to understand...= =<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20840 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20840 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20840\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20854\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RosyIsh\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/2476/avatar/89dff08f92b47321.jpg'/> </a>\n <div><a href=\"/profile/RosyIsh\" title=\"Expert RosyIsh\" class=\"rated-user user-blue\">RosyIsh</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 09:53\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20854\" href=\"?#comment-20854\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20854\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"2476\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20854\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div><div>I can't clearly understand the solution to B here.</div><div>I submitted an O(M*K) in the contest which passed.</div><div><br /></div><div>Now, I tried another approach using fenwick tree , complexity O(M log N + K log N) which passed too. Here's a link to see the code : <a href=\"http://pastebin.com/SAeFbdcG\">http://pastebin.com/SAeFbdcG</a></div><div><br /></div><div>Is this what is intended in the tutorial or a much simpler solution ?<br /></div></div><div><br /></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20854 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20854 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20854\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20859\" commentParentId=\"20854\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RedAnt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/550/avatar/a60953c6a6e6562a.jpg'/> </a>\n <div><a href=\"/profile/RedAnt\" title=\"Expert RedAnt\" class=\"rated-user user-blue\">RedAnt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 11:19\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20859\" href=\"?#comment-20859\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20854\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20859\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20859\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"550\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20859\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">As constraints for n are small, we can mark values on the number line and update the current values, as we walk through. Here is a O(m+k+n) <a href=\"http://www.ideone.com/CcTUY\">http://www.ideone.com/CcTUY</a></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20859 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20859 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20859\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20874\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/the_saint\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/11054/avatar/9d5201d3625a6201.jpg'/> </a>\n <div><a href=\"/profile/the_saint\" title=\"Candidate Master the_saint\" class=\"rated-user user-violet\">the_saint</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:33\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20874\" href=\"?#comment-20874\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20874\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"11054\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20874\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I'm not that good at maths and although I knew little Fermat's theorem before, using it in that way was something new to me. <div><br /></div><div>But what if the module wasn't a primer number? In the contest I used dp to calculate the combination and my approach isn't depended by the module. I'm curious if there is a way (maybe involving math) different than this if the module isn't prime?</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20874 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20874 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20874\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20875\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/ant.ermilov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/452/avatar/26a5367a89736db7.jpg'/> </a>\n <div><a href=\"/profile/ant.ermilov\" title=\"Expert ant.ermilov\" class=\"rated-user user-blue\">ant.ermilov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:46\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20875\" href=\"?#comment-20875\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20875\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"452\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20875\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Theoretically you can use <a href=\"https://en.wikipedia.org/wiki/Chinese_remainder_theorem\">Chinese remainder theorem</a> on prime factorization of module and then restore answer.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20875 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20875 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20875\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20893\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Urbanowicz\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/Urbanowicz\" title=\"Expert Urbanowicz\" class=\"rated-user user-blue\">Urbanowicz</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 17:26\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20893\" href=\"?#comment-20893\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20893\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20893\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"11366\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20893\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><a>Euler's totient theorem</a> is a generalization of Fermat's one and works for any module. Also you can solve <span class=\"tex-span\"><i>ax</i> ≡ 1</span> (mod b) equation by solving its equivalent Diophantine equation <span class=\"tex-span\"><i>ax</i> + <i>by</i> = 1</span> with extended Euclidean algorithm.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20893 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20893 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20893\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20933\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/havaliza\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/402/avatar/f5a24cdc4359b26.jpg'/> </a>\n <div><a href=\"/profile/havaliza\" title=\"Candidate Master havaliza\" class=\"rated-user user-violet\">havaliza</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 23:04\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20933\" href=\"?#comment-20933\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20933\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20933\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"402\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20933\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">I didn't use any thing about prime module in my solution. For all prime numbers between 1 and 2n-1 I just computed their power in C(2n-1, n) and then multiplied the result with it. Computing the power was easy, like computing the number of first zero digits of n!. It ran in 130ms.<br />Here is my code: http://pastebin.com/Xieb5PuP<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20933 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20933 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20933\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20922\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 21:30\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20922\" href=\"?#comment-20922\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20922\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20922\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20922\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Thanks for the tutorial. But I cant understand the explanation of problem C. The explanation is very confusing :(<span style=\"font-family: arial;line-height: normal;font-size: small;\"><br /></span></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20922 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20922 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20922\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20952\" commentParentId=\"20922\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 01:57\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20952\" href=\"?#comment-20952\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20922\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20952\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"1\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+1</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20952\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Try <a href=\"//codeforces.com/blog/entry/1169#comment-20773\">this one</a>.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20952 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20952 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20952\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20977\" commentParentId=\"20952\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 13:03\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20977\" href=\"?#comment-20977\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20952\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20977\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20977\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you very much :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20977 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20977 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20977\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20989\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/looc\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/looc\" title=\"Unrated, looc\" class=\"rated-user user-black\">looc</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 17:50\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20989\" href=\"?#comment-20989\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20989\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"12456\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20989\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In problem D, i am facing a tough time in finding the sum of manhattan distances in O(max(n^2 ,m^2)). Can someone give me a hint? :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20989 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20989 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20989\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20991\" commentParentId=\"20989\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 19:32\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20991\" href=\"?#comment-20991\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20989\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20991\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20991\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">The sum of Manhattan distances over all cells: <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7a81e71722ed9132468b80c15f6e451c5f2b85f6.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/4ded835a280e330bc0ce060e978554a1454375f4.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7409ac8b1c963c0a9884ac2a550fab38702d8302.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />.<br /><br />Now we need to subtract the sum of Manhattan distances with occupied cells. Suppose <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span> is one of occupied cells, then <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/917e8a7b9262bb634b6460dc2199659511615898.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. Since there are at most <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span> occupied cells, we can just sum over all <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span>.<br /><br />Finally, the pairs of occupied cells were subtracted twice and we need to add them back. It's <span class=\"tex-span\"><i>O</i>(<i>max</i>(<i>n</i><sup class=\"upper-index\">2</sup>, <i>m</i><sup class=\"upper-index\">2</sup>))</span> as well.<br /><br />And don't forget that the order of cells matters, so for example the sums in the second paragraph above need to be multiplied by 2.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20991 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20991 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20991\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1181\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"}}},{"rowIdx":295,"cells":{"problem_id":{"kind":"string","value":"57B"},"contest":{"kind":"string","value":"57"},"problem":{"kind":"string","value":"B"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"B. Martian Architecture"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Martian Architecture</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Chris the Rabbit found the traces of an ancient Martian civilization. The brave astronomer managed to see through a small telescope an architecture masterpiece — \"A Road to the Sun\". The building stands on cubical stones of the same size. The foundation divides the entire \"road\" into cells, into which the cubical stones are fit tightly. Thus, to any cell of the foundation a coordinate can be assigned. To become the leader of the tribe, a Martian should build a Road to the Sun, that is to build from those cubical stones on a given foundation a stairway. The stairway should be described by the number of stones in the initial coordinate and the coordinates of the stairway's beginning and end. Each following cell in the coordinate's increasing order should contain one cubical stone more than the previous one. At that if the cell has already got stones, they do not count in this building process, the stairways were simply built on them. In other words, let us assume that a stairway is built with the initial coordinate of <span class=\"tex-span\"><i>l</i></span>, the final coordinate of <span class=\"tex-span\"><i>r</i></span> and the number of stones in the initial coordinate <span class=\"tex-span\"><i>x</i></span>. That means that <span class=\"tex-span\"><i>x</i></span> stones <span class=\"tex-font-style-bf\">will be added</span> in the cell <span class=\"tex-span\"><i>l</i></span>, <span class=\"tex-span\"><i>x</i> + 1</span> stones will be added in the cell <span class=\"tex-span\"><i>l</i> + 1</span>, ..., <span class=\"tex-span\"><i>x</i> + <i>r</i> - <i>l</i></span> stones will be added in the cell <span class=\"tex-span\"><i>r</i></span>.</p><p>Chris managed to find an ancient manuscript, containing the descriptions of all the stairways. Now he wants to compare the data to be sure that he has really found \"A Road to the Sun\". For that he chose some road cells and counted the total number of cubical stones that has been accumulated throughout the Martian history and then asked you to count using the manuscript to what the sum should ideally total.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three space-separated integers: <span class=\"tex-span\"><i>n</i>, <i>m</i>, <i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 10<sup class=\"upper-index\">5</sup>, 1 ≤ <i>k</i> ≤ <i>min</i>(<i>n</i>, 100)</span>) which is the number of cells, the number of \"Roads to the Sun\" and the number of cells in the query correspondingly. Each of the following <span class=\"tex-span\"><i>m</i></span> roads contain three space-separated integers: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub>, <i>b</i><sub class=\"lower-index\"><i>i</i></sub>, <i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>b</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i>, 1 ≤ <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 1000</span>) which are the stairway's description, its beginning, end and the initial cell's height. Then follow a line, containing <span class=\"tex-span\"><i>k</i></span> different space-separated integers <span class=\"tex-span\"><i>b</i><sub class=\"lower-index\"><i>i</i></sub></span>. All these numbers ranging from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span> are cells, the number of stones in which interests Chris.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You have to print a single number on a single line which is the sum of stones in all the cells Chris is interested in.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 2 1<br/>1 5 1<br/>2 4 1<br/>3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 2 1<br/>1 3 1<br/>1 3 1<br/>2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 2 1<br/>1 3 1<br/>1 3 1<br/>3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"e39a59eabe3a8d23fb9e56b8aedeb57b\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - B - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"ac67dea8cf3109b0107a111cd3f3e199fc14c4b4\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - B - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/57\">Codeforces Beta Round 53</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='e39a59eabe3a8d23fb9e56b8aedeb57b'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/57/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Implementation problems, programming technics, simulation\">\r\n implementation\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1600\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='e39a59eabe3a8d23fb9e56b8aedeb57b'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"298\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='e39a59eabe3a8d23fb9e56b8aedeb57b'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"298\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1165\" title=\"Codeforces Beta Round #53\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"209:210\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1171\" title=\"Codeforces Beta Round #53 [Analysis]\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"812:813\" resourceName=\"Tutorial\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: 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class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">B. Martian Architecture</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Chris the Rabbit found the traces of an ancient Martian civilization. The brave astronomer managed to see through a small telescope an architecture masterpiece — "A Road to the Sun". The building stands on cubical stones of the same size. The foundation divides the entire "road" into cells, into which the cubical stones are fit tightly. Thus, to any cell of the foundation a coordinate can be assigned. To become the leader of the tribe, a Martian should build a Road to the Sun, that is to build from those cubical stones on a given foundation a stairway. The stairway should be described by the number of stones in the initial coordinate and the coordinates of the stairway's beginning and end. Each following cell in the coordinate's increasing order should contain one cubical stone more than the previous one. At that if the cell has already got stones, they do not count in this building process, the stairways were simply built on them. In other words, let us assume that a stairway is built with the initial coordinate of <span class=\"tex-span\"><i>l</i></span>, the final coordinate of <span class=\"tex-span\"><i>r</i></span> and the number of stones in the initial coordinate <span class=\"tex-span\"><i>x</i></span>. That means that <span class=\"tex-span\"><i>x</i></span> stones <span class=\"tex-font-style-bf\">will be added</span> in the cell <span class=\"tex-span\"><i>l</i></span>, <span class=\"tex-span\"><i>x</i> + 1</span> stones will be added in the cell <span class=\"tex-span\"><i>l</i> + 1</span>, ..., <span class=\"tex-span\"><i>x</i> + <i>r</i> - <i>l</i></span> stones will be added in the cell <span class=\"tex-span\"><i>r</i></span>.</p><p>Chris managed to find an ancient manuscript, containing the descriptions of all the stairways. Now he wants to compare the data to be sure that he has really found "A Road to the Sun". For that he chose some road cells and counted the total number of cubical stones that has been accumulated throughout the Martian history and then asked you to count using the manuscript to what the sum should ideally total.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains three space-separated integers: <span class=\"tex-span\"><i>n</i>, <i>m</i>, <i>k</i></span> (<span class=\"tex-span\">1 ≤ <i>n</i>, <i>m</i> ≤ 10<sup class=\"upper-index\">5</sup>, 1 ≤ <i>k</i> ≤ <i>min</i>(<i>n</i>, 100)</span>) which is the number of cells, the number of "Roads to the Sun" and the number of cells in the query correspondingly. Each of the following <span class=\"tex-span\"><i>m</i></span> roads contain three space-separated integers: <span class=\"tex-span\"><i>a</i><sub class=\"lower-index\"><i>i</i></sub>, <i>b</i><sub class=\"lower-index\"><i>i</i></sub>, <i>c</i><sub class=\"lower-index\"><i>i</i></sub></span> (<span class=\"tex-span\">1 ≤ <i>a</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>b</i><sub class=\"lower-index\"><i>i</i></sub> ≤ <i>n</i>, 1 ≤ <i>c</i><sub class=\"lower-index\"><i>i</i></sub> ≤ 1000</span>) which are the stairway's description, its beginning, end and the initial cell's height. Then follow a line, containing <span class=\"tex-span\"><i>k</i></span> different space-separated integers <span class=\"tex-span\"><i>b</i><sub class=\"lower-index\"><i>i</i></sub></span>. All these numbers ranging from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span> are cells, the number of stones in which interests Chris.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You have to print a single number on a single line which is the sum of stones in all the cells Chris is interested in.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>5 2 1<br />1 5 1<br />2 4 1<br />3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>5<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 2 1<br />1 3 1<br />1 3 1<br />2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 2 1<br />1 3 1<br />1 3 1<br />3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>6<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=B]\");\r\n let uuid = 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='ce6ca9373d76d422a834978ac82e9761'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/nevidomy\">nevidomy</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/nevidomy\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/nevidomy\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/nevidomy\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/nevidomy\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/nevidomy\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/nevidomy\" style=\"text-decoration:none;color:black !important;\">nevidomy's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1171\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1171\"> Codeforces Beta Round #53 [Analysis]\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/nevidomy\" title=\"Candidate Master nevidomy\" class=\"rated-user user-violet\">nevidomy</a>,\r\n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h3></h3><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"verdana, arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem А.</span></font><br /></h3><p style=\"margin-top: 1.0em;margin-right: 0.0px;margin-bottom: 1.0em;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-size: 12.0px;line-height: 20.0px;font-family: Verdana;font-weight: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;line-height: normal;font-size: small;\"></span></font></p><p><font face=\"Arial, sans-serif\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Since the restrictions were not so big you can offer many different solutions. For example, you can construct a graph with N * 4 vertices and use bfs. But there was a faster solution with complexity O(1): enumerate the integer points lying on the square, for example, as is shown below:</span></span><span style=\"font-size: 9.0pt;font-family: Verdana , sans-serif;\"></span></font></p><p style=\"font-family: verdana , arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><img src=\"https://vnevidomy.narod2.ru/images/a-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Then finding the number of a point by its coordinates isn’t difficult. For example if a point has coordinate y == n -> then its position is n + x (if the numeration, is as shown, i.e. starts with zero). It turns out that we have transformed the square into a line with a small complication: cells N * 4 - 1 and 0 are adjacent, so we have not a line but a circle, where for the base points from 0 to 4 * N-1 the distance between the adjacent two points is 1. It is easy to take the difference of indices of the points and find the distance when moving clockwise and counterclockwise: (a-b +4 * n)% (4 * n) and (b - a + 4 * n)% (4 * n), the shortest distance will be the answer.</span></span></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem B</span></h3><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-size: 10.0pt;font-family: Arial , sans-serif;color: black;\">Under the restrictions on the number of requests, you cannot iteratively add staircase. But the problem is simplified by the fact that the number of cells in which it was necessary to know the number of stones was no more than 100. That’s why you can check for each "interesting" cell all the queries and calculate how much each of them adds stones, so the complexity is: O (K * M), which fits within the given 2 seconds well. A faster solution with complexity O(N + M + K) is as follows: we will keep in mind two variables: a – how many items should be added now to the cell, v - how much should change a next step. So problem is to update the value of a and v so that a equaled to the number of stones in the cell after all the operations, and v – to how much a increases during the transition to the next cell. Then the problem will be reduced to that you need to properly update a and v, which is not very difficult to do, for example if there is a request (x, y, z) – then in the cell x you need to add x to a and add 1 to v, since with each next cell the number of stones for some staircase will increase by 1. Similarly, after the cell y is passed you need to subtract 1 from v and pick up from “a” the current number of stones subquery. If you save all such pairs of queries in a single array and it's possible to calculate everything in one cycle.</span></span><span style=\"color: black;\"></span></font></p><p><font face=\"arial\" size=\"2\"></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"arial\" size=\"2\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem C</span></font></font></h3><p style=\"color: black;font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">First, let's count how many there are arrays in which each successive element starting from the second one is no less than the previous one. To do this quickly, let’s take a piece of squared with height of one square and the length of N*2 - 1 square, then select N-1 squares and put crosses in them - let it encode some array, let the number of blank cells from the beginning of the array before the first cross be equal to the number of ones in the array, the number of blank cells from the first cross to the second – to the number of 2 in the array, and so on. It is easy to see that the number of empty cells will be equal to N * 2-1 - (N-1) = N. It turns out that each paper encodes an array which suits us, and moreover all the possible arrays can be encoded using such paper. There is exactly C (N * 2-1, N) different pieces of paper (the binomial coefficient of N * 2-1 to N). This number can be calculated by formula with factorials, the only difficulty is division. Since the module was prime - it was possible to calculate the inverse number in the field for the module and replace division by multiplication. So we get the number of non-decreasing sequences, respectively have the same number of non-increasing, we just need to take away those who were represented in both array sets, but they are just arrays with a similar number like {1,1,1,...,1} or {4,4,...,4,4} just subtract n.</span></span><span style=\"font-size: 9.0pt;font-family: Arial , sans-serif;color: black;\"></span></font></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem D</span></font></h3><p style=\"color: black;font-family: Arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><span><span lang=\"RU\" style=\"font-family: Arial , sans-serif;color: black;\"></span></span></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Let's see, if there is no occupied cells, then it is not difficult to calculate the answer - the answer is a sum of Manhattan distances, taking into account the fact that the Manhattan distance can be divided: first we can calculate the distance of one coordinate and then of another one and then just to sum up, so the answer is not difficult to find. What do we have when there are occupied cells? If the cell from which we seek the distance does not lie on the same horizontal or vertical with occupied cells – then it absolutely does not affect the difficulty of accessing the rest of the cells:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">This happens due to the fact that in each cell from the previous distance front (the distance to the set of cells with maximum distance from the start cell, the fronts form a diamond as you can see in the picture or from the Manhattan distance formula) there are two ways how to get to the cell, we take into account the rule that no two cells can be adjacent (either diagonally or vertically or horizontally), it turns out that such a cell does not interfere with us. But a close look at the picture brings to mind the obvious: it is the cell which is located on the same vertical / horizontal that has only one neighbor from the previous front, let’s see what happens in such case:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-2.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;font-size: small;\">All the cells after occupied one starts "to lag" at 2 in distance, but more importantly, that changed the front! Now (with the upper side of the front) are 2 cells for which the transition from the previous front is unique, and as a consequence there are two cells meeting of which will produce a new segment of a late cells, and the angle of the front will change again. Since we are only interested in one side of its expansion (on the other hand there can not be occupied cells by the condition) so we can assume that it was expand from the start cell:</span><br /></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-3.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">It turns out that you can count how many cells will be "delayed", especially considering that the lag always equals to two. For each direction, you can choose each occupied cell and check in the left and right directions for adjacent cells series, and add delay for interval of free cell before occupied cell (in the current direction). It is possible to calculate such delays with complexity: square of the number of occupied cells (it is not greater than min(N, M)). The rest is details. You need to compute all Manhattan distances, taking into account the existence of occupied cells. To do this, first calculate the sum of distances for an empty field, then for each occupied cell calculate the distance to all the others - subtract it twice, as the extra distance is subtracted for the first time when we got out of this cell and for the second time when takes away from all other cells to the given one. But in this case we will take away twice the distance between two occupied cells - so we’ll have to add them (the complexity is also a square). A total complexity of solution is O (K ^ 2) where K is the number of occupied cells.</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem E</span></font></h3><h3 style=\"font-weight: normal;\"><span style=\"font-weight: normal;\"><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">The task turned out to be very difficult as it was planned. First remove all the deleted cells - let's see how changes the number of accessible cells with the increase of the new moves. First, the changes do not appear stable, but at some point we see a figure which won’t to change the form anymore and will only expand, it is obvious that the figure is two-dimensional, therefore the growth of its “area” is a quadratic function, in fact, a simple check shows that with each new turn the number of cells increases by the number of new cells opened with previous turn + 28, so after a certain point, you can simply take the sum of an arithmetic progression. The case with the deleted cells is similar. In general, there are several possible options - either occupied cells block further penetration of the horse or not, in the first case bfs is simply enough to find solutions, in the second one the story is the same: over time, when the figure "becomes balanced", the number of new opened cells satisfies the same rule "prev +28" . Moreover, because of restrictions of the coordinates of the deleted cells (-10 <= x, y <= 10) this happens fairly quickly. So, use usual bfs to balance figures, and after this use the sum of the arithmetic progression.</span></span><span style=\"color: black;\"></span></font></p></span></h3></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/57\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 53</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-296-1171\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"296\",\n blogEntryId: \"1171\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+53\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 53</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+24</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/nevidomy\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/nevidomy\">\n nevidomy\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1171#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1171#comments\">\n 15\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1181\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (12)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20840\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lyrics\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3858/avatar/29787cdba9b12888.jpg'/> </a>\n <div><a href=\"/profile/lyrics\" title=\"Expert lyrics\" class=\"rated-user user-blue\">lyrics</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 04:43\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20840\" href=\"?#comment-20840\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20840\" revisionCount=\"5\" revision=\"5\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">5</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20840\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"3858\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20840\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">the translation is a bit difficult to understand...= =<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20840 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20840 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20840\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20854\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RosyIsh\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/2476/avatar/89dff08f92b47321.jpg'/> </a>\n <div><a href=\"/profile/RosyIsh\" title=\"Expert RosyIsh\" class=\"rated-user user-blue\">RosyIsh</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 09:53\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20854\" href=\"?#comment-20854\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20854\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"2476\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20854\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div><div>I can't clearly understand the solution to B here.</div><div>I submitted an O(M*K) in the contest which passed.</div><div><br /></div><div>Now, I tried another approach using fenwick tree , complexity O(M log N + K log N) which passed too. Here's a link to see the code : <a href=\"http://pastebin.com/SAeFbdcG\">http://pastebin.com/SAeFbdcG</a></div><div><br /></div><div>Is this what is intended in the tutorial or a much simpler solution ?<br /></div></div><div><br /></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20854 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20854 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20854\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20859\" commentParentId=\"20854\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RedAnt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/550/avatar/a60953c6a6e6562a.jpg'/> </a>\n <div><a href=\"/profile/RedAnt\" title=\"Expert RedAnt\" class=\"rated-user user-blue\">RedAnt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 11:19\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20859\" href=\"?#comment-20859\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20854\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20859\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20859\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"550\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20859\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">As constraints for n are small, we can mark values on the number line and update the current values, as we walk through. Here is a O(m+k+n) <a href=\"http://www.ideone.com/CcTUY\">http://www.ideone.com/CcTUY</a></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20859 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20859 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20859\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20874\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/the_saint\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/11054/avatar/9d5201d3625a6201.jpg'/> </a>\n <div><a href=\"/profile/the_saint\" title=\"Candidate Master the_saint\" class=\"rated-user user-violet\">the_saint</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:33\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20874\" href=\"?#comment-20874\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20874\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"11054\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20874\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I'm not that good at maths and although I knew little Fermat's theorem before, using it in that way was something new to me. <div><br /></div><div>But what if the module wasn't a primer number? In the contest I used dp to calculate the combination and my approach isn't depended by the module. I'm curious if there is a way (maybe involving math) different than this if the module isn't prime?</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20874 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20874 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20874\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20875\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/ant.ermilov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/452/avatar/26a5367a89736db7.jpg'/> </a>\n <div><a href=\"/profile/ant.ermilov\" title=\"Expert ant.ermilov\" class=\"rated-user user-blue\">ant.ermilov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:46\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20875\" href=\"?#comment-20875\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20875\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"452\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20875\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Theoretically you can use <a href=\"https://en.wikipedia.org/wiki/Chinese_remainder_theorem\">Chinese remainder theorem</a> on prime factorization of module and then restore answer.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20875 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20875 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20875\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20893\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Urbanowicz\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/Urbanowicz\" title=\"Expert Urbanowicz\" class=\"rated-user user-blue\">Urbanowicz</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 17:26\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20893\" href=\"?#comment-20893\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20893\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20893\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"11366\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20893\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><a>Euler's totient theorem</a> is a generalization of Fermat's one and works for any module. Also you can solve <span class=\"tex-span\"><i>ax</i> ≡ 1</span> (mod b) equation by solving its equivalent Diophantine equation <span class=\"tex-span\"><i>ax</i> + <i>by</i> = 1</span> with extended Euclidean algorithm.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20893 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20893 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20893\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20933\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/havaliza\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/402/avatar/f5a24cdc4359b26.jpg'/> </a>\n <div><a href=\"/profile/havaliza\" title=\"Candidate Master havaliza\" class=\"rated-user user-violet\">havaliza</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 23:04\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20933\" href=\"?#comment-20933\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20933\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20933\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"402\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20933\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">I didn't use any thing about prime module in my solution. For all prime numbers between 1 and 2n-1 I just computed their power in C(2n-1, n) and then multiplied the result with it. Computing the power was easy, like computing the number of first zero digits of n!. It ran in 130ms.<br />Here is my code: http://pastebin.com/Xieb5PuP<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20933 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20933 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20933\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20922\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 21:30\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20922\" href=\"?#comment-20922\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20922\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20922\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20922\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Thanks for the tutorial. But I cant understand the explanation of problem C. The explanation is very confusing :(<span style=\"font-family: arial;line-height: normal;font-size: small;\"><br /></span></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20922 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20922 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20922\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20952\" commentParentId=\"20922\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 01:57\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20952\" href=\"?#comment-20952\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20922\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20952\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"1\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+1</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20952\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Try <a href=\"//codeforces.com/blog/entry/1169#comment-20773\">this one</a>.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20952 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20952 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20952\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20977\" commentParentId=\"20952\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 13:03\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20977\" href=\"?#comment-20977\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20952\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20977\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20977\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you very much :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20977 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20977 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20977\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20989\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/looc\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/looc\" title=\"Unrated, looc\" class=\"rated-user user-black\">looc</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 17:50\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20989\" href=\"?#comment-20989\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20989\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"12456\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20989\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In problem D, i am facing a tough time in finding the sum of manhattan distances in O(max(n^2 ,m^2)). Can someone give me a hint? :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20989 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20989 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20989\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20991\" commentParentId=\"20989\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 19:32\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20991\" href=\"?#comment-20991\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20989\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20991\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20991\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">The sum of Manhattan distances over all cells: <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7a81e71722ed9132468b80c15f6e451c5f2b85f6.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/4ded835a280e330bc0ce060e978554a1454375f4.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7409ac8b1c963c0a9884ac2a550fab38702d8302.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />.<br /><br />Now we need to subtract the sum of Manhattan distances with occupied cells. Suppose <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span> is one of occupied cells, then <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/917e8a7b9262bb634b6460dc2199659511615898.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. Since there are at most <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span> occupied cells, we can just sum over all <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span>.<br /><br />Finally, the pairs of occupied cells were subtracted twice and we need to add them back. It's <span class=\"tex-span\"><i>O</i>(<i>max</i>(<i>n</i><sup class=\"upper-index\">2</sup>, <i>m</i><sup class=\"upper-index\">2</sup>))</span> as well.<br /><br />And don't forget that the order of cells matters, so for example the sums in the second paragraph above need to be multiplied by 2.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20991 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20991 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20991\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1181\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 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Array"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Array</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Chris the Rabbit has been interested in arrays ever since he was a child. At the moment he is researching arrays with the length of <span class=\"tex-span\"><i>n</i></span>, containing only integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. He is not good at math, that's why some simple things drive him crazy. For example, yesterday he grew keen on counting how many different beautiful arrays there are. Chris thinks that an array is beautiful if it meets one of the two conditions: </p><ul> <li> each elements, starting from the second one, is no more than the preceding one </li><li> each element, starting from the second one, is no less than the preceding one </li></ul><p>Having got absolutely mad at himself and at math, Chris came to Stewie and Brian to ask them for help. However, they only laughed at him and said that the answer is too simple and not interesting. Help Chris the Rabbit to find the answer at last.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The single line contains an integer <span class=\"tex-span\"><i>n</i></span> which is the size of the array (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">5</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You must print the answer on a single line. As it can be rather long, you should print it modulo <span class=\"tex-span\">1000000007</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>17<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"5884cc000e9c3cc2ede8824ac6d979af\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - C - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"ac67dea8cf3109b0107a111cd3f3e199fc14c4b4\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - C - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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\"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1165\" title=\"Codeforces Beta Round #53\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"209:210\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1171\" title=\"Codeforces Beta Round #53 [Analysis]\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"812:813\" resourceName=\"Tutorial\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/57\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/57/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/57/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/57/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/57/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/57/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/57/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/57/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if (node.tagName === \"SCRIPT\" || node.tagName === \"math\"\r\n || (node.classList && node.classList.contains(\"input-output-copier\")))\r\n return [];\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(OPENING_SPACE);\r\n }\r\n\r\n if (node.nodeType === Node.TEXT_NODE) {\r\n let s = node.textContent;\r\n if (!pre) {\r\n s = s.replace(/\\s+/g, \" \");\r\n }\r\n if (s.length > 0) {\r\n result.push(s);\r\n }\r\n }\r\n\r\n if (pre && node.tagName === \"BR\") {\r\n result.push(\"\\n\");\r\n }\r\n\r\n node.childNodes.forEach(function (child) {\r\n result.push(nodeToText(child, node.tagName === \"PRE\").join(\"\"));\r\n });\r\n\r\n if (node.tagName === \"DIV\"\r\n || node.tagName === \"P\"\r\n || node.tagName === \"PRE\"\r\n || node.tagName === \"UL\"\r\n || node.tagName === \"LI\"\r\n ) {\r\n result.push(\"\\n\");\r\n }\r\n\r\n if (node.tagName === \"NOBR\") {\r\n result.push(CLOSING_SPACE);\r\n }\r\n\r\n return result;\r\n }\r\n\r\n const isSpecial = function (c) {\r\n return c === ',' || c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"C\" data-uuid=\"ps_1244989cedec63d3eac1b5012b7eda4ea8860d4a\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">C. Array</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Chris the Rabbit has been interested in arrays ever since he was a child. At the moment he is researching arrays with the length of <span class=\"tex-span\"><i>n</i></span>, containing only integers from <span class=\"tex-span\">1</span> to <span class=\"tex-span\"><i>n</i></span>. He is not good at math, that's why some simple things drive him crazy. For example, yesterday he grew keen on counting how many different beautiful arrays there are. Chris thinks that an array is beautiful if it meets one of the two conditions: </p><ul> <li> each elements, starting from the second one, is no more than the preceding one </li><li> each element, starting from the second one, is no less than the preceding one </li></ul><p>Having got absolutely mad at himself and at math, Chris came to Stewie and Brian to ask them for help. However, they only laughed at him and said that the answer is too simple and not interesting. Help Chris the Rabbit to find the answer at last.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The single line contains an integer <span class=\"tex-span\"><i>n</i></span> which is the size of the array (<span class=\"tex-span\">1 ≤ <i>n</i> ≤ 10<sup class=\"upper-index\">5</sup></span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You must print the answer on a single line. As it can be rather long, you should print it modulo <span class=\"tex-span\">1000000007</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>4<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>17<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=C]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n 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data-clipboard-target='#\" + preId + \"' id='\" + cpyId + \"' class='input-output-copier'>Copy</div>\");\r\n $(this).append($copy);\r\n\r\n const clipboard = new Clipboard('#' + cpyId, {\r\n text: function (trigger) {\r\n const pre = document.querySelector('#' + preId);\r\n const lines = pre.querySelectorAll(\".test-example-line\");\r\n return Codeforces.filterClipboardText(pre.innerText, lines.length);\r\n }\r\n });\r\n\r\n const isInput = $(this).parent().hasClass(\"input\");\r\n\r\n clipboard.on('success', function (e) {\r\n if (isInput) {\r\n Codeforces.showMessage(\"The example input has been copied into the clipboard\");\r\n } else {\r\n Codeforces.showMessage(\"The example output has been copied into the clipboard\");\r\n }\r\n e.clearSelection();\r\n });\r\n });\r\n\r\n $(\".test-form-item input\").change(function () {\r\n addPendingSubmissionMessage($($(this).closest(\"form\")), \"You changed the answer, do not forget to submit it if you want to save the changes\");\r\n const 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='ce6ca9373d76d422a834978ac82e9761'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/nevidomy\">nevidomy</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/nevidomy\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/nevidomy\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/nevidomy\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/nevidomy\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/nevidomy\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/nevidomy\" style=\"text-decoration:none;color:black !important;\">nevidomy's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1171\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1171\"> Codeforces Beta Round #53 [Analysis]\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/nevidomy\" title=\"Candidate Master nevidomy\" class=\"rated-user user-violet\">nevidomy</a>,\r\n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h3></h3><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"verdana, arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem А.</span></font><br /></h3><p style=\"margin-top: 1.0em;margin-right: 0.0px;margin-bottom: 1.0em;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-size: 12.0px;line-height: 20.0px;font-family: Verdana;font-weight: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;line-height: normal;font-size: small;\"></span></font></p><p><font face=\"Arial, sans-serif\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Since the restrictions were not so big you can offer many different solutions. For example, you can construct a graph with N * 4 vertices and use bfs. But there was a faster solution with complexity O(1): enumerate the integer points lying on the square, for example, as is shown below:</span></span><span style=\"font-size: 9.0pt;font-family: Verdana , sans-serif;\"></span></font></p><p style=\"font-family: verdana , arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><img src=\"https://vnevidomy.narod2.ru/images/a-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Then finding the number of a point by its coordinates isn’t difficult. For example if a point has coordinate y == n -> then its position is n + x (if the numeration, is as shown, i.e. starts with zero). It turns out that we have transformed the square into a line with a small complication: cells N * 4 - 1 and 0 are adjacent, so we have not a line but a circle, where for the base points from 0 to 4 * N-1 the distance between the adjacent two points is 1. It is easy to take the difference of indices of the points and find the distance when moving clockwise and counterclockwise: (a-b +4 * n)% (4 * n) and (b - a + 4 * n)% (4 * n), the shortest distance will be the answer.</span></span></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem B</span></h3><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-size: 10.0pt;font-family: Arial , sans-serif;color: black;\">Under the restrictions on the number of requests, you cannot iteratively add staircase. But the problem is simplified by the fact that the number of cells in which it was necessary to know the number of stones was no more than 100. That’s why you can check for each "interesting" cell all the queries and calculate how much each of them adds stones, so the complexity is: O (K * M), which fits within the given 2 seconds well. A faster solution with complexity O(N + M + K) is as follows: we will keep in mind two variables: a – how many items should be added now to the cell, v - how much should change a next step. So problem is to update the value of a and v so that a equaled to the number of stones in the cell after all the operations, and v – to how much a increases during the transition to the next cell. Then the problem will be reduced to that you need to properly update a and v, which is not very difficult to do, for example if there is a request (x, y, z) – then in the cell x you need to add x to a and add 1 to v, since with each next cell the number of stones for some staircase will increase by 1. Similarly, after the cell y is passed you need to subtract 1 from v and pick up from “a” the current number of stones subquery. If you save all such pairs of queries in a single array and it's possible to calculate everything in one cycle.</span></span><span style=\"color: black;\"></span></font></p><p><font face=\"arial\" size=\"2\"></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"arial\" size=\"2\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem C</span></font></font></h3><p style=\"color: black;font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">First, let's count how many there are arrays in which each successive element starting from the second one is no less than the previous one. To do this quickly, let’s take a piece of squared with height of one square and the length of N*2 - 1 square, then select N-1 squares and put crosses in them - let it encode some array, let the number of blank cells from the beginning of the array before the first cross be equal to the number of ones in the array, the number of blank cells from the first cross to the second – to the number of 2 in the array, and so on. It is easy to see that the number of empty cells will be equal to N * 2-1 - (N-1) = N. It turns out that each paper encodes an array which suits us, and moreover all the possible arrays can be encoded using such paper. There is exactly C (N * 2-1, N) different pieces of paper (the binomial coefficient of N * 2-1 to N). This number can be calculated by formula with factorials, the only difficulty is division. Since the module was prime - it was possible to calculate the inverse number in the field for the module and replace division by multiplication. So we get the number of non-decreasing sequences, respectively have the same number of non-increasing, we just need to take away those who were represented in both array sets, but they are just arrays with a similar number like {1,1,1,...,1} or {4,4,...,4,4} just subtract n.</span></span><span style=\"font-size: 9.0pt;font-family: Arial , sans-serif;color: black;\"></span></font></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem D</span></font></h3><p style=\"color: black;font-family: Arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><span><span lang=\"RU\" style=\"font-family: Arial , sans-serif;color: black;\"></span></span></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Let's see, if there is no occupied cells, then it is not difficult to calculate the answer - the answer is a sum of Manhattan distances, taking into account the fact that the Manhattan distance can be divided: first we can calculate the distance of one coordinate and then of another one and then just to sum up, so the answer is not difficult to find. What do we have when there are occupied cells? If the cell from which we seek the distance does not lie on the same horizontal or vertical with occupied cells – then it absolutely does not affect the difficulty of accessing the rest of the cells:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">This happens due to the fact that in each cell from the previous distance front (the distance to the set of cells with maximum distance from the start cell, the fronts form a diamond as you can see in the picture or from the Manhattan distance formula) there are two ways how to get to the cell, we take into account the rule that no two cells can be adjacent (either diagonally or vertically or horizontally), it turns out that such a cell does not interfere with us. But a close look at the picture brings to mind the obvious: it is the cell which is located on the same vertical / horizontal that has only one neighbor from the previous front, let’s see what happens in such case:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-2.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;font-size: small;\">All the cells after occupied one starts "to lag" at 2 in distance, but more importantly, that changed the front! Now (with the upper side of the front) are 2 cells for which the transition from the previous front is unique, and as a consequence there are two cells meeting of which will produce a new segment of a late cells, and the angle of the front will change again. Since we are only interested in one side of its expansion (on the other hand there can not be occupied cells by the condition) so we can assume that it was expand from the start cell:</span><br /></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-3.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">It turns out that you can count how many cells will be "delayed", especially considering that the lag always equals to two. For each direction, you can choose each occupied cell and check in the left and right directions for adjacent cells series, and add delay for interval of free cell before occupied cell (in the current direction). It is possible to calculate such delays with complexity: square of the number of occupied cells (it is not greater than min(N, M)). The rest is details. You need to compute all Manhattan distances, taking into account the existence of occupied cells. To do this, first calculate the sum of distances for an empty field, then for each occupied cell calculate the distance to all the others - subtract it twice, as the extra distance is subtracted for the first time when we got out of this cell and for the second time when takes away from all other cells to the given one. But in this case we will take away twice the distance between two occupied cells - so we’ll have to add them (the complexity is also a square). A total complexity of solution is O (K ^ 2) where K is the number of occupied cells.</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem E</span></font></h3><h3 style=\"font-weight: normal;\"><span style=\"font-weight: normal;\"><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">The task turned out to be very difficult as it was planned. First remove all the deleted cells - let's see how changes the number of accessible cells with the increase of the new moves. First, the changes do not appear stable, but at some point we see a figure which won’t to change the form anymore and will only expand, it is obvious that the figure is two-dimensional, therefore the growth of its “area” is a quadratic function, in fact, a simple check shows that with each new turn the number of cells increases by the number of new cells opened with previous turn + 28, so after a certain point, you can simply take the sum of an arithmetic progression. The case with the deleted cells is similar. In general, there are several possible options - either occupied cells block further penetration of the horse or not, in the first case bfs is simply enough to find solutions, in the second one the story is the same: over time, when the figure "becomes balanced", the number of new opened cells satisfies the same rule "prev +28" . Moreover, because of restrictions of the coordinates of the deleted cells (-10 <= x, y <= 10) this happens fairly quickly. So, use usual bfs to balance figures, and after this use the sum of the arithmetic progression.</span></span><span style=\"color: black;\"></span></font></p></span></h3></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/57\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 53</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-296-1171\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"296\",\n blogEntryId: \"1171\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+53\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 53</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+24</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/nevidomy\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/nevidomy\">\n nevidomy\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1171#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1171#comments\">\n 15\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1181\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (12)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20840\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lyrics\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3858/avatar/29787cdba9b12888.jpg'/> </a>\n <div><a href=\"/profile/lyrics\" title=\"Expert lyrics\" class=\"rated-user user-blue\">lyrics</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 04:43\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20840\" href=\"?#comment-20840\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20840\" revisionCount=\"5\" revision=\"5\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">5</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20840\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"3858\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20840\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">the translation is a bit difficult to understand...= =<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20840 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20840 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20840\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20854\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RosyIsh\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/2476/avatar/89dff08f92b47321.jpg'/> </a>\n <div><a href=\"/profile/RosyIsh\" title=\"Expert RosyIsh\" class=\"rated-user user-blue\">RosyIsh</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 09:53\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20854\" href=\"?#comment-20854\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20854\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"2476\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20854\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div><div>I can't clearly understand the solution to B here.</div><div>I submitted an O(M*K) in the contest which passed.</div><div><br /></div><div>Now, I tried another approach using fenwick tree , complexity O(M log N + K log N) which passed too. Here's a link to see the code : <a href=\"http://pastebin.com/SAeFbdcG\">http://pastebin.com/SAeFbdcG</a></div><div><br /></div><div>Is this what is intended in the tutorial or a much simpler solution ?<br /></div></div><div><br /></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20854 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20854 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20854\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20859\" commentParentId=\"20854\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RedAnt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/550/avatar/a60953c6a6e6562a.jpg'/> </a>\n <div><a href=\"/profile/RedAnt\" title=\"Expert RedAnt\" class=\"rated-user user-blue\">RedAnt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 11:19\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20859\" href=\"?#comment-20859\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20854\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20859\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20859\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"550\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20859\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">As constraints for n are small, we can mark values on the number line and update the current values, as we walk through. Here is a O(m+k+n) <a href=\"http://www.ideone.com/CcTUY\">http://www.ideone.com/CcTUY</a></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20859 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20859 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20859\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20874\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/the_saint\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/11054/avatar/9d5201d3625a6201.jpg'/> </a>\n <div><a href=\"/profile/the_saint\" title=\"Candidate Master the_saint\" class=\"rated-user user-violet\">the_saint</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:33\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20874\" href=\"?#comment-20874\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20874\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"11054\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20874\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I'm not that good at maths and although I knew little Fermat's theorem before, using it in that way was something new to me. <div><br /></div><div>But what if the module wasn't a primer number? In the contest I used dp to calculate the combination and my approach isn't depended by the module. I'm curious if there is a way (maybe involving math) different than this if the module isn't prime?</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20874 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20874 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20874\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20875\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/ant.ermilov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/452/avatar/26a5367a89736db7.jpg'/> </a>\n <div><a href=\"/profile/ant.ermilov\" title=\"Expert ant.ermilov\" class=\"rated-user user-blue\">ant.ermilov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:46\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20875\" href=\"?#comment-20875\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20875\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"452\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20875\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Theoretically you can use <a href=\"https://en.wikipedia.org/wiki/Chinese_remainder_theorem\">Chinese remainder theorem</a> on prime factorization of module and then restore answer.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20875 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20875 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20875\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20893\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Urbanowicz\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/Urbanowicz\" title=\"Expert Urbanowicz\" class=\"rated-user user-blue\">Urbanowicz</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 17:26\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20893\" href=\"?#comment-20893\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20893\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20893\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"11366\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20893\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><a>Euler's totient theorem</a> is a generalization of Fermat's one and works for any module. Also you can solve <span class=\"tex-span\"><i>ax</i> ≡ 1</span> (mod b) equation by solving its equivalent Diophantine equation <span class=\"tex-span\"><i>ax</i> + <i>by</i> = 1</span> with extended Euclidean algorithm.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20893 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20893 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20893\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20933\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/havaliza\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/402/avatar/f5a24cdc4359b26.jpg'/> </a>\n <div><a href=\"/profile/havaliza\" title=\"Candidate Master havaliza\" class=\"rated-user user-violet\">havaliza</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 23:04\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20933\" href=\"?#comment-20933\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20933\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20933\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"402\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20933\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">I didn't use any thing about prime module in my solution. For all prime numbers between 1 and 2n-1 I just computed their power in C(2n-1, n) and then multiplied the result with it. Computing the power was easy, like computing the number of first zero digits of n!. It ran in 130ms.<br />Here is my code: http://pastebin.com/Xieb5PuP<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20933 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20933 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20933\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20922\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 21:30\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20922\" href=\"?#comment-20922\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20922\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20922\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20922\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Thanks for the tutorial. But I cant understand the explanation of problem C. The explanation is very confusing :(<span style=\"font-family: arial;line-height: normal;font-size: small;\"><br /></span></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20922 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20922 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20922\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20952\" commentParentId=\"20922\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 01:57\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20952\" href=\"?#comment-20952\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20922\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20952\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"1\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+1</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20952\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Try <a href=\"//codeforces.com/blog/entry/1169#comment-20773\">this one</a>.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20952 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20952 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20952\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20977\" commentParentId=\"20952\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 13:03\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20977\" href=\"?#comment-20977\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20952\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20977\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20977\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you very much :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20977 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20977 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20977\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20989\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/looc\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/looc\" title=\"Unrated, looc\" class=\"rated-user user-black\">looc</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 17:50\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20989\" href=\"?#comment-20989\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20989\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"12456\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20989\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In problem D, i am facing a tough time in finding the sum of manhattan distances in O(max(n^2 ,m^2)). Can someone give me a hint? :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20989 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20989 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20989\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20991\" commentParentId=\"20989\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 19:32\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20991\" href=\"?#comment-20991\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20989\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20991\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20991\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">The sum of Manhattan distances over all cells: <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7a81e71722ed9132468b80c15f6e451c5f2b85f6.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/4ded835a280e330bc0ce060e978554a1454375f4.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7409ac8b1c963c0a9884ac2a550fab38702d8302.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />.<br /><br />Now we need to subtract the sum of Manhattan distances with occupied cells. Suppose <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span> is one of occupied cells, then <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/917e8a7b9262bb634b6460dc2199659511615898.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. Since there are at most <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span> occupied cells, we can just sum over all <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span>.<br /><br />Finally, the pairs of occupied cells were subtracted twice and we need to add them back. It's <span class=\"tex-span\"><i>O</i>(<i>max</i>(<i>n</i><sup class=\"upper-index\">2</sup>, <i>m</i><sup class=\"upper-index\">2</sup>))</span> as well.<br /><br />And don't forget that the order of cells matters, so for example the sums in the second paragraph above need to be multiplied by 2.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20991 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20991 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20991\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1181\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"}}},{"rowIdx":297,"cells":{"problem_id":{"kind":"string","value":"57D"},"contest":{"kind":"string","value":"57"},"problem":{"kind":"string","value":"D"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"D. Journey"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Journey</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Stewie the Rabbit explores a new parallel universe. This two dimensional universe has the shape of a rectangular grid, containing <span class=\"tex-span\"><i>n</i></span> lines and <span class=\"tex-span\"><i>m</i></span> columns. The universe is very small: one cell of the grid can only contain one particle. Each particle in this universe is either static or dynamic. Each static particle always remains in one and the same position. Due to unintelligible gravitation laws no two static particles in the parallel universe can be present in one column or row, and they also can't be present in the diagonally <span class=\"tex-font-style-bf\">adjacent</span> cells. A dynamic particle appears in a random empty cell, randomly chooses the destination cell (destination cell may coincide with the start cell, see the samples) and moves there along the shortest path through the cells, unoccupied by the static particles. All empty cells have the same probability of being selected as the beginning or end of the path. Having reached the destination cell, the particle disappears. Only one dynamic particle can exist at one moment of time. This particle can move from a cell to a cell if they have an adjacent side, and this transition takes exactly one galactic second. Stewie got interested in what is the average lifespan of one particle in the given universe.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two space-separated integers: <span class=\"tex-span\"><i>n</i>, <i>m</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i>, <i>m</i> ≤ 1000</span>) which represent the sizes of the universe. The next <span class=\"tex-span\"><i>n</i></span> lines containing <span class=\"tex-span\"><i>m</i></span> symbols each describe the universe without dynamic particles — the <span class=\"tex-span\"><i>j</i></span>-th symbol of the <span class=\"tex-span\"><i>i</i></span>-th line equals to <span class=\"tex-font-style-tt\">'X'</span> if the cell is occupied by a static particle, and to <span class=\"tex-font-style-tt\">'.'</span> if it is empty. It is guaranteed that the described universe satisfies the properties described above, that is no two static particles can be in one column or in one row, besides, they can't be positioned in the diagonally adjacent cells.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You have to print on a single line a single number which is the average life span of a particle with an accuracy of at least 6 decimal places.</p><p>The answer will be accepted if it is within <span class=\"tex-span\">10<sup class=\"upper-index\"> - 6</sup></span> of absolute or relative error from the correct answer.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2<br/>..<br/>.X<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.888888888889<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br/>...<br/>.X.<br/>...<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2.000000000000<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"0032277b035ec5a61c9d20a868abc505\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - D - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"ac67dea8cf3109b0107a111cd3f3e199fc14c4b4\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - D - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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\"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1165\" title=\"Codeforces Beta Round #53\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"209:210\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1171\" title=\"Codeforces Beta Round #53 [Analysis]\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"812:813\" resourceName=\"Tutorial\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/57\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/57/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/57/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/57/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/57/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/57/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/57/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/57/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if 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|| c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"D\" data-uuid=\"ps_27607bc0423aa78482d73001ab1a4c0c20a3b5f4\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">D. Journey</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Stewie the Rabbit explores a new parallel universe. This two dimensional universe has the shape of a rectangular grid, containing <span class=\"tex-span\"><i>n</i></span> lines and <span class=\"tex-span\"><i>m</i></span> columns. The universe is very small: one cell of the grid can only contain one particle. Each particle in this universe is either static or dynamic. Each static particle always remains in one and the same position. Due to unintelligible gravitation laws no two static particles in the parallel universe can be present in one column or row, and they also can't be present in the diagonally <span class=\"tex-font-style-bf\">adjacent</span> cells. A dynamic particle appears in a random empty cell, randomly chooses the destination cell (destination cell may coincide with the start cell, see the samples) and moves there along the shortest path through the cells, unoccupied by the static particles. All empty cells have the same probability of being selected as the beginning or end of the path. Having reached the destination cell, the particle disappears. Only one dynamic particle can exist at one moment of time. This particle can move from a cell to a cell if they have an adjacent side, and this transition takes exactly one galactic second. Stewie got interested in what is the average lifespan of one particle in the given universe.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two space-separated integers: <span class=\"tex-span\"><i>n</i>, <i>m</i></span> (<span class=\"tex-span\">2 ≤ <i>n</i>, <i>m</i> ≤ 1000</span>) which represent the sizes of the universe. The next <span class=\"tex-span\"><i>n</i></span> lines containing <span class=\"tex-span\"><i>m</i></span> symbols each describe the universe without dynamic particles — the <span class=\"tex-span\"><i>j</i></span>-th symbol of the <span class=\"tex-span\"><i>i</i></span>-th line equals to <span class=\"tex-font-style-tt\">'X'</span> if the cell is occupied by a static particle, and to <span class=\"tex-font-style-tt\">'.'</span> if it is empty. It is guaranteed that the described universe satisfies the properties described above, that is no two static particles can be in one column or in one row, besides, they can't be positioned in the diagonally adjacent cells.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You have to print on a single line a single number which is the average life span of a particle with an accuracy of at least 6 decimal places.</p><p>The answer will be accepted if it is within <span class=\"tex-span\">10<sup class=\"upper-index\"> - 6</sup></span> of absolute or relative error from the correct answer.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>2 2<br />..<br />.X<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>0.888888888889<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>3 3<br />...<br />.X.<br />...<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>2.000000000000<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=D]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if (previousStatementText !== statementText) {\r\n $problem.find(\".diff-notifier\").show();\r\n\r\n $problem.find(\".diff-notifier-close\").click(function() {\r\n Codeforces.putToStorageTtl(uuid, statementText, 6 * 60 * 60);\r\n $problem.find(\".diff-notifier\").hide();\r\n });\r\n\r\n $problem.find(\"a.view-changes\").click(function() {\r\n $.post(\"/data/diff\", {action: \"getDiff\", a: previousStatementText, b: statementText}, function (result) {\r\n if 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dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='ce6ca9373d76d422a834978ac82e9761'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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href=\"/profile/nevidomy\">nevidomy</a></li>\r\n <li class=\"current selectedLava\"><a\r\n href=\"/blog/nevidomy\">Blog</a></li>\r\n <li><a\r\n href=\"/teams/with/nevidomy\">Teams</a></li>\r\n <li><a\r\n href=\"/submissions/nevidomy\">Submissions</a></li>\r\n <li><a\r\n href=\"/contests/with/nevidomy\">Contests</a></li>\r\n <li><a\r\n href=\"/contests/writer/nevidomy\">Problemsetting</a></li>\r\n</ul>\r\n</div>\n <div style=\"margin-top:0;\">\r\n <div>\r\n <h3><a href=\"/blog/nevidomy\" style=\"text-decoration:none;color:black !important;\">nevidomy's blog</a></h3>\r\n </div>\r\n <div style=\"margin-top:2em;\">\r\n\r\n\r\n<div class=\"has-topic-id topic\" topicId=\"1171\">\r\n <div class=\"title\">\r\n <a href=\"/blog/entry/1171\"> Codeforces Beta Round #53 [Analysis]\r\n</a>\r\n </div>\r\n\r\n <div class=\"info\" style=\"position:relative;\">\r\n By <a href=\"/profile/nevidomy\" title=\"Candidate Master nevidomy\" class=\"rated-user user-violet\">nevidomy</a>,\r\n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h3></h3><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"verdana, arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem А.</span></font><br /></h3><p style=\"margin-top: 1.0em;margin-right: 0.0px;margin-bottom: 1.0em;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-size: 12.0px;line-height: 20.0px;font-family: Verdana;font-weight: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;line-height: normal;font-size: small;\"></span></font></p><p><font face=\"Arial, sans-serif\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Since the restrictions were not so big you can offer many different solutions. For example, you can construct a graph with N * 4 vertices and use bfs. But there was a faster solution with complexity O(1): enumerate the integer points lying on the square, for example, as is shown below:</span></span><span style=\"font-size: 9.0pt;font-family: Verdana , sans-serif;\"></span></font></p><p style=\"font-family: verdana , arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><img src=\"https://vnevidomy.narod2.ru/images/a-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Then finding the number of a point by its coordinates isn’t difficult. For example if a point has coordinate y == n -> then its position is n + x (if the numeration, is as shown, i.e. starts with zero). It turns out that we have transformed the square into a line with a small complication: cells N * 4 - 1 and 0 are adjacent, so we have not a line but a circle, where for the base points from 0 to 4 * N-1 the distance between the adjacent two points is 1. It is easy to take the difference of indices of the points and find the distance when moving clockwise and counterclockwise: (a-b +4 * n)% (4 * n) and (b - a + 4 * n)% (4 * n), the shortest distance will be the answer.</span></span></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem B</span></h3><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-size: 10.0pt;font-family: Arial , sans-serif;color: black;\">Under the restrictions on the number of requests, you cannot iteratively add staircase. But the problem is simplified by the fact that the number of cells in which it was necessary to know the number of stones was no more than 100. That’s why you can check for each "interesting" cell all the queries and calculate how much each of them adds stones, so the complexity is: O (K * M), which fits within the given 2 seconds well. A faster solution with complexity O(N + M + K) is as follows: we will keep in mind two variables: a – how many items should be added now to the cell, v - how much should change a next step. So problem is to update the value of a and v so that a equaled to the number of stones in the cell after all the operations, and v – to how much a increases during the transition to the next cell. Then the problem will be reduced to that you need to properly update a and v, which is not very difficult to do, for example if there is a request (x, y, z) – then in the cell x you need to add x to a and add 1 to v, since with each next cell the number of stones for some staircase will increase by 1. Similarly, after the cell y is passed you need to subtract 1 from v and pick up from “a” the current number of stones subquery. If you save all such pairs of queries in a single array and it's possible to calculate everything in one cycle.</span></span><span style=\"color: black;\"></span></font></p><p><font face=\"arial\" size=\"2\"></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"arial\" size=\"2\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem C</span></font></font></h3><p style=\"color: black;font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">First, let's count how many there are arrays in which each successive element starting from the second one is no less than the previous one. To do this quickly, let’s take a piece of squared with height of one square and the length of N*2 - 1 square, then select N-1 squares and put crosses in them - let it encode some array, let the number of blank cells from the beginning of the array before the first cross be equal to the number of ones in the array, the number of blank cells from the first cross to the second – to the number of 2 in the array, and so on. It is easy to see that the number of empty cells will be equal to N * 2-1 - (N-1) = N. It turns out that each paper encodes an array which suits us, and moreover all the possible arrays can be encoded using such paper. There is exactly C (N * 2-1, N) different pieces of paper (the binomial coefficient of N * 2-1 to N). This number can be calculated by formula with factorials, the only difficulty is division. Since the module was prime - it was possible to calculate the inverse number in the field for the module and replace division by multiplication. So we get the number of non-decreasing sequences, respectively have the same number of non-increasing, we just need to take away those who were represented in both array sets, but they are just arrays with a similar number like {1,1,1,...,1} or {4,4,...,4,4} just subtract n.</span></span><span style=\"font-size: 9.0pt;font-family: Arial , sans-serif;color: black;\"></span></font></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem D</span></font></h3><p style=\"color: black;font-family: Arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><span><span lang=\"RU\" style=\"font-family: Arial , sans-serif;color: black;\"></span></span></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Let's see, if there is no occupied cells, then it is not difficult to calculate the answer - the answer is a sum of Manhattan distances, taking into account the fact that the Manhattan distance can be divided: first we can calculate the distance of one coordinate and then of another one and then just to sum up, so the answer is not difficult to find. What do we have when there are occupied cells? If the cell from which we seek the distance does not lie on the same horizontal or vertical with occupied cells – then it absolutely does not affect the difficulty of accessing the rest of the cells:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">This happens due to the fact that in each cell from the previous distance front (the distance to the set of cells with maximum distance from the start cell, the fronts form a diamond as you can see in the picture or from the Manhattan distance formula) there are two ways how to get to the cell, we take into account the rule that no two cells can be adjacent (either diagonally or vertically or horizontally), it turns out that such a cell does not interfere with us. But a close look at the picture brings to mind the obvious: it is the cell which is located on the same vertical / horizontal that has only one neighbor from the previous front, let’s see what happens in such case:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-2.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;font-size: small;\">All the cells after occupied one starts "to lag" at 2 in distance, but more importantly, that changed the front! Now (with the upper side of the front) are 2 cells for which the transition from the previous front is unique, and as a consequence there are two cells meeting of which will produce a new segment of a late cells, and the angle of the front will change again. Since we are only interested in one side of its expansion (on the other hand there can not be occupied cells by the condition) so we can assume that it was expand from the start cell:</span><br /></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-3.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">It turns out that you can count how many cells will be "delayed", especially considering that the lag always equals to two. For each direction, you can choose each occupied cell and check in the left and right directions for adjacent cells series, and add delay for interval of free cell before occupied cell (in the current direction). It is possible to calculate such delays with complexity: square of the number of occupied cells (it is not greater than min(N, M)). The rest is details. You need to compute all Manhattan distances, taking into account the existence of occupied cells. To do this, first calculate the sum of distances for an empty field, then for each occupied cell calculate the distance to all the others - subtract it twice, as the extra distance is subtracted for the first time when we got out of this cell and for the second time when takes away from all other cells to the given one. But in this case we will take away twice the distance between two occupied cells - so we’ll have to add them (the complexity is also a square). A total complexity of solution is O (K ^ 2) where K is the number of occupied cells.</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem E</span></font></h3><h3 style=\"font-weight: normal;\"><span style=\"font-weight: normal;\"><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">The task turned out to be very difficult as it was planned. First remove all the deleted cells - let's see how changes the number of accessible cells with the increase of the new moves. First, the changes do not appear stable, but at some point we see a figure which won’t to change the form anymore and will only expand, it is obvious that the figure is two-dimensional, therefore the growth of its “area” is a quadratic function, in fact, a simple check shows that with each new turn the number of cells increases by the number of new cells opened with previous turn + 28, so after a certain point, you can simply take the sum of an arithmetic progression. The case with the deleted cells is similar. In general, there are several possible options - either occupied cells block further penetration of the horse or not, in the first case bfs is simply enough to find solutions, in the second one the story is the same: over time, when the figure "becomes balanced", the number of new opened cells satisfies the same rule "prev +28" . Moreover, because of restrictions of the coordinates of the deleted cells (-10 <= x, y <= 10) this happens fairly quickly. So, use usual bfs to balance figures, and after this use the sum of the arithmetic progression.</span></span><span style=\"color: black;\"></span></font></p></span></h3></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/57\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 53</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-296-1171\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"296\",\n blogEntryId: \"1171\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+53\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 53</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+24</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/nevidomy\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/nevidomy\">\n nevidomy\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1171#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1171#comments\">\n 15\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1181\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (12)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20840\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lyrics\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3858/avatar/29787cdba9b12888.jpg'/> </a>\n <div><a href=\"/profile/lyrics\" title=\"Expert lyrics\" class=\"rated-user user-blue\">lyrics</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 04:43\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20840\" href=\"?#comment-20840\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20840\" revisionCount=\"5\" revision=\"5\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">5</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20840\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"3858\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20840\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">the translation is a bit difficult to understand...= =<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20840 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20840 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20840\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20854\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RosyIsh\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/2476/avatar/89dff08f92b47321.jpg'/> </a>\n <div><a href=\"/profile/RosyIsh\" title=\"Expert RosyIsh\" class=\"rated-user user-blue\">RosyIsh</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 09:53\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20854\" href=\"?#comment-20854\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20854\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"2476\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20854\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div><div>I can't clearly understand the solution to B here.</div><div>I submitted an O(M*K) in the contest which passed.</div><div><br /></div><div>Now, I tried another approach using fenwick tree , complexity O(M log N + K log N) which passed too. Here's a link to see the code : <a href=\"http://pastebin.com/SAeFbdcG\">http://pastebin.com/SAeFbdcG</a></div><div><br /></div><div>Is this what is intended in the tutorial or a much simpler solution ?<br /></div></div><div><br /></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20854 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20854 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20854\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20859\" commentParentId=\"20854\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RedAnt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/550/avatar/a60953c6a6e6562a.jpg'/> </a>\n <div><a href=\"/profile/RedAnt\" title=\"Expert RedAnt\" class=\"rated-user user-blue\">RedAnt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 11:19\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20859\" href=\"?#comment-20859\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20854\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20859\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20859\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"550\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20859\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">As constraints for n are small, we can mark values on the number line and update the current values, as we walk through. Here is a O(m+k+n) <a href=\"http://www.ideone.com/CcTUY\">http://www.ideone.com/CcTUY</a></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20859 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20859 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20859\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20874\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/the_saint\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/11054/avatar/9d5201d3625a6201.jpg'/> </a>\n <div><a href=\"/profile/the_saint\" title=\"Candidate Master the_saint\" class=\"rated-user user-violet\">the_saint</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:33\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20874\" href=\"?#comment-20874\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20874\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"11054\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20874\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I'm not that good at maths and although I knew little Fermat's theorem before, using it in that way was something new to me. <div><br /></div><div>But what if the module wasn't a primer number? In the contest I used dp to calculate the combination and my approach isn't depended by the module. I'm curious if there is a way (maybe involving math) different than this if the module isn't prime?</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20874 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20874 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20874\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20875\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/ant.ermilov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/452/avatar/26a5367a89736db7.jpg'/> </a>\n <div><a href=\"/profile/ant.ermilov\" title=\"Expert ant.ermilov\" class=\"rated-user user-blue\">ant.ermilov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:46\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20875\" href=\"?#comment-20875\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20875\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"452\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20875\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Theoretically you can use <a href=\"https://en.wikipedia.org/wiki/Chinese_remainder_theorem\">Chinese remainder theorem</a> on prime factorization of module and then restore answer.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20875 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20875 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20875\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20893\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Urbanowicz\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/Urbanowicz\" title=\"Expert Urbanowicz\" class=\"rated-user user-blue\">Urbanowicz</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 17:26\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20893\" href=\"?#comment-20893\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20893\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20893\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"11366\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20893\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><a>Euler's totient theorem</a> is a generalization of Fermat's one and works for any module. Also you can solve <span class=\"tex-span\"><i>ax</i> ≡ 1</span> (mod b) equation by solving its equivalent Diophantine equation <span class=\"tex-span\"><i>ax</i> + <i>by</i> = 1</span> with extended Euclidean algorithm.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20893 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20893 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20893\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20933\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/havaliza\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/402/avatar/f5a24cdc4359b26.jpg'/> </a>\n <div><a href=\"/profile/havaliza\" title=\"Candidate Master havaliza\" class=\"rated-user user-violet\">havaliza</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 23:04\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20933\" href=\"?#comment-20933\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20933\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20933\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"402\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20933\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">I didn't use any thing about prime module in my solution. For all prime numbers between 1 and 2n-1 I just computed their power in C(2n-1, n) and then multiplied the result with it. Computing the power was easy, like computing the number of first zero digits of n!. It ran in 130ms.<br />Here is my code: http://pastebin.com/Xieb5PuP<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20933 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20933 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20933\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20922\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 21:30\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20922\" href=\"?#comment-20922\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20922\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20922\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20922\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Thanks for the tutorial. But I cant understand the explanation of problem C. The explanation is very confusing :(<span style=\"font-family: arial;line-height: normal;font-size: small;\"><br /></span></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20922 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20922 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20922\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20952\" commentParentId=\"20922\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 01:57\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20952\" href=\"?#comment-20952\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20922\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20952\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"1\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+1</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20952\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Try <a href=\"//codeforces.com/blog/entry/1169#comment-20773\">this one</a>.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20952 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20952 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20952\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20977\" commentParentId=\"20952\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 13:03\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20977\" href=\"?#comment-20977\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20952\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20977\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20977\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you very much :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20977 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20977 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20977\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20989\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/looc\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/looc\" title=\"Unrated, looc\" class=\"rated-user user-black\">looc</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 17:50\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20989\" href=\"?#comment-20989\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20989\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"12456\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20989\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In problem D, i am facing a tough time in finding the sum of manhattan distances in O(max(n^2 ,m^2)). Can someone give me a hint? :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20989 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20989 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20989\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20991\" commentParentId=\"20989\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 19:32\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20991\" href=\"?#comment-20991\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20989\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20991\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20991\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">The sum of Manhattan distances over all cells: <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7a81e71722ed9132468b80c15f6e451c5f2b85f6.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/4ded835a280e330bc0ce060e978554a1454375f4.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7409ac8b1c963c0a9884ac2a550fab38702d8302.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />.<br /><br />Now we need to subtract the sum of Manhattan distances with occupied cells. Suppose <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span> is one of occupied cells, then <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/917e8a7b9262bb634b6460dc2199659511615898.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. Since there are at most <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span> occupied cells, we can just sum over all <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span>.<br /><br />Finally, the pairs of occupied cells were subtracted twice and we need to add them back. It's <span class=\"tex-span\"><i>O</i>(<i>max</i>(<i>n</i><sup class=\"upper-index\">2</sup>, <i>m</i><sup class=\"upper-index\">2</sup>))</span> as well.<br /><br />And don't forget that the order of cells matters, so for example the sums in the second paragraph above need to be multiplied by 2.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20991 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20991 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20991\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1181\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 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Chess"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Chess</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Brian the Rabbit adores chess. Not long ago he argued with Stewie the Rabbit that a knight is better than a king. To prove his point he tries to show that the knight is very fast but Stewie doesn't accept statements without evidence. He constructed an infinite chessboard for Brian, where he deleted several squares to add some more interest to the game. Brian only needs to count how many different board squares a knight standing on a square with coordinates of <span class=\"tex-span\">(0, 0)</span> can reach in no more than <span class=\"tex-span\"><i>k</i></span> moves. Naturally, it is forbidden to move to the deleted squares.</p><p>Brian doesn't very much like exact sciences himself and is not acquainted with programming, that's why he will hardly be able to get ahead of Stewie who has already started solving the problem. Help Brian to solve the problem faster than Stewie.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two integers <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">0 ≤ <i>k</i> ≤ 10<sup class=\"upper-index\">18</sup>, 0 ≤ <i>n</i> ≤ 440</span>) which are correspondingly the maximal number of moves a knight can make and the number of deleted cells. Then follow <span class=\"tex-span\"><i>n</i></span> lines, each giving the coordinates of a deleted square in the form <span class=\"tex-span\">(<i>x</i><sub class=\"lower-index\"><i>i</i></sub>, <i>y</i><sub class=\"lower-index\"><i>i</i></sub>)</span> (<span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\"><i>i</i></sub>| ≤ 10, |<i>y</i><sub class=\"lower-index\"><i>i</i></sub>| ≤ 10</span>). All the numbers are integer, the deleted squares are different and it is guaranteed that the square <span class=\"tex-span\">(0, 0)</span> is not deleted.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You must print the answer on a single line. As it can be rather long, you should print it modulo <span class=\"tex-span\">1000000007</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1 0<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 7<br/>-1 2<br/>1 2<br/>2 1<br/>2 -1<br/>1 -2<br/>-1 -2<br/>-2 -1<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"1b8b05ddef00f7b0b04319d867172af4\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - E - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"ac67dea8cf3109b0107a111cd3f3e199fc14c4b4\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - E - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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To adjust the time limit constraint, a solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then the value 800 ms will be displayed and used to determine the verdict.\r\n </div>\r\n </div>\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:100%;\"><a style=\"color: black\" href=\"/contest/57\">Codeforces Beta Round 53</a></th>\n </tr>\n <tr>\n <td class=\"left bottom\" colspan=\"1\"><span class=\"contest-state-phase\">Finished</span></td>\n </tr>\n </tbody>\n </table>\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Practice?\n <div class=\"top-links\">\n </div>\n </div>\n<div>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Want to solve the contest problems after the official contest ends? 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It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/57/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = 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data-uuid=\"ps_f79fb616d6a1efa702de76273846fca3b7f208c7\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">E. Chess</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>2 seconds</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Brian the Rabbit adores chess. Not long ago he argued with Stewie the Rabbit that a knight is better than a king. To prove his point he tries to show that the knight is very fast but Stewie doesn't accept statements without evidence. He constructed an infinite chessboard for Brian, where he deleted several squares to add some more interest to the game. Brian only needs to count how many different board squares a knight standing on a square with coordinates of <span class=\"tex-span\">(0, 0)</span> can reach in no more than <span class=\"tex-span\"><i>k</i></span> moves. Naturally, it is forbidden to move to the deleted squares.</p><p>Brian doesn't very much like exact sciences himself and is not acquainted with programming, that's why he will hardly be able to get ahead of Stewie who has already started solving the problem. Help Brian to solve the problem faster than Stewie.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first line contains two integers <span class=\"tex-span\"><i>k</i></span> and <span class=\"tex-span\"><i>n</i></span> (<span class=\"tex-span\">0 ≤ <i>k</i> ≤ 10<sup class=\"upper-index\">18</sup>, 0 ≤ <i>n</i> ≤ 440</span>) which are correspondingly the maximal number of moves a knight can make and the number of deleted cells. Then follow <span class=\"tex-span\"><i>n</i></span> lines, each giving the coordinates of a deleted square in the form <span class=\"tex-span\">(<i>x</i><sub class=\"lower-index\"><i>i</i></sub>, <i>y</i><sub class=\"lower-index\"><i>i</i></sub>)</span> (<span class=\"tex-span\">|<i>x</i><sub class=\"lower-index\"><i>i</i></sub>| ≤ 10, |<i>y</i><sub class=\"lower-index\"><i>i</i></sub>| ≤ 10</span>). All the numbers are integer, the deleted squares are different and it is guaranteed that the square <span class=\"tex-span\">(0, 0)</span> is not deleted.</p><p>Please, do not use <span class=\"tex-font-style-tt\">%lld</span> specificator to read or write 64-bit integers in C++. It is preffered to use <span class=\"tex-font-style-tt\">cin</span> (also you may use <span class=\"tex-font-style-tt\">%I64d</span>).</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>You must print the answer on a single line. As it can be rather long, you should print it modulo <span class=\"tex-span\">1000000007</span>.</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>1 0<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>2 7<br />-1 2<br />1 2<br />2 1<br />2 -1<br />1 -2<br />-1 -2<br />-2 -1<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>9<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=E]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let statementText = convertStatementToText($problem.find(\".ttypography\").get(0));\r\n\r\n let previousStatementText = Codeforces.getFromStorage(uuid);\r\n if (previousStatementText) {\r\n if 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Extra registration opens 10 minutes after the contest starts and lasts 25 minutes.\"></i></div>\r\n </div>\r\n</div>\r\n </div>\n\n<style data-nocturne=\"true\" type=\"text/css\">\n._StreamsSidebarFrame_frame {\n padding: 0.5em 0.5em 0 0.5em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream {\n text-align: center;\n border-bottom: 1px solid #b9b9b9;\n margin: 0 -0.5em 0.5em -0.5em;\n padding: 0 1em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_user {\n margin: 0 0 0.5em 0;\n font-size: 0.8em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream ._StreamsSidebarFrame_timeMark {\n color: #777;\n font-size: 0.9em;\n}\n._StreamsSidebarFrame_frame ._StreamsSidebarFrame_stream:last-of-type {\n border-bottom: unset;\n margin: unset;\n padding: 0 0.5em 0.5em 1em;\n}\n._StreamsSidebarFrame_frame ._viewAll {\n text-align: right;\n}\n.moreRunningStreamsSidebarNote {\n color: #777 !important;\n text-decoration: none;\n}\n</style>\n\n\n<script data-nocturne=\"true\"> $(function () {\n\n}); </script>\n\n<div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Top rated\n<div class=\"top-links\">\n</div>\n</div>\n<table class=\"rtable \">\n<tbody>\n<tr>\n<th class=\"left\" style=\"width:2.25em;\">#</th>\n<th class=\"\">User</th>\n<th class=\"\" style=\"width:5em;\">Rating</th>\n</tr>\n<tr>\n<td class=\"left dark\">1</td>\n<td class=\" dark\"><a href=\"/profile/tourist\" title=\"Legendary Grandmaster tourist\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">t</span>ourist</a></td>\n<td class=\" dark\">3775</td>\n</tr>\n<tr>\n<td class=\"left \">2</td>\n<td class=\"\"><a href=\"/profile/Benq\" title=\"Legendary Grandmaster Benq\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">B</span>enq</a></td>\n<td class=\"\">3724</td>\n</tr>\n<tr>\n<td class=\"left dark\">3</td>\n<td class=\" dark\"><a href=\"/profile/orzdevinwang\" title=\"Legendary Grandmaster orzdevinwang\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">o</span>rzdevinwang</a></td>\n<td class=\" dark\">3697</td>\n</tr>\n<tr>\n<td class=\"left \">4</td>\n<td class=\"\"><a href=\"/profile/Radewoosh\" title=\"Legendary Grandmaster Radewoosh\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>adewoosh</a></td>\n<td class=\"\">3651</td>\n</tr>\n<tr>\n<td class=\"left dark\">5</td>\n<td class=\" dark\"><a href=\"/profile/jiangly\" title=\"Legendary Grandmaster jiangly\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">j</span>iangly</a></td>\n<td class=\" dark\">3632</td>\n</tr>\n<tr>\n<td class=\"left \">6</td>\n<td class=\"\"><a href=\"/profile/cnnfls_csy\" title=\"Legendary Grandmaster cnnfls_csy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='ce6ca9373d76d422a834978ac82e9761'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a> →\r\n <a href=\"/blog/entry/121073\">Meta Hacker Cup 2023 Round 1</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pyqe\" title=\"International Grandmaster Pyqe\" class=\"rated-user user-red\">Pyqe</a> →\r\n <a href=\"/blog/entry/121025\">Codeforces Round #902 (Div. 1, Div. 2, based on COMPFEST 15 — Final Round)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/Pranshu_Pandya\" title=\"Specialist Pranshu_Pandya\" class=\"rated-user user-cyan\">Pranshu_Pandya</a> →\r\n <a href=\"/blog/entry/121171\">An Interesting Tree Problem</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/.Danet\" title=\"Expert .Danet\" class=\"rated-user user-blue\">.Danet</a> →\r\n <a href=\"/blog/entry/121172\">[TLE on pretest1]</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" style=\"vertical-align:middle;\"/>\r\n</div>\r\n</li>\r\n <li><div style=\"font-size:0.9em;padding:0.5em 0;\">\r\n<a href=\"/profile/sszcdjr\" title=\"Master sszcdjr\" class=\"rated-user user-orange\">sszcdjr</a> →\r\n <a href=\"/blog/entry/119859\">Codeforces Round 896 (Div. 1, Div. 2)</a>\r\n <img alt=\"New comment(s)\" title=\"New comment(s)\" src=\"//codeforces.org/s/81027/images/icons/comment-12x12.png\" 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class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><h3></h3><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"verdana, arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem А.</span></font><br /></h3><p style=\"margin-top: 1.0em;margin-right: 0.0px;margin-bottom: 1.0em;margin-left: 0.0px;padding-top: 0.0px;padding-right: 0.0px;padding-bottom: 0.0px;padding-left: 0.0px;font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-size: 12.0px;line-height: 20.0px;font-family: Verdana;font-weight: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;line-height: normal;font-size: small;\"></span></font></p><p><font face=\"Arial, sans-serif\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Since the restrictions were not so big you can offer many different solutions. For example, you can construct a graph with N * 4 vertices and use bfs. But there was a faster solution with complexity O(1): enumerate the integer points lying on the square, for example, as is shown below:</span></span><span style=\"font-size: 9.0pt;font-family: Verdana , sans-serif;\"></span></font></p><p style=\"font-family: verdana , arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><img src=\"https://vnevidomy.narod2.ru/images/a-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Then finding the number of a point by its coordinates isn’t difficult. For example if a point has coordinate y == n -> then its position is n + x (if the numeration, is as shown, i.e. starts with zero). It turns out that we have transformed the square into a line with a small complication: cells N * 4 - 1 and 0 are adjacent, so we have not a line but a circle, where for the base points from 0 to 4 * N-1 the distance between the adjacent two points is 1. It is easy to take the difference of indices of the points and find the distance when moving clockwise and counterclockwise: (a-b +4 * n)% (4 * n) and (b - a + 4 * n)% (4 * n), the shortest distance will be the answer.</span></span></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem B</span></h3><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-size: 10.0pt;font-family: Arial , sans-serif;color: black;\">Under the restrictions on the number of requests, you cannot iteratively add staircase. But the problem is simplified by the fact that the number of cells in which it was necessary to know the number of stones was no more than 100. That’s why you can check for each "interesting" cell all the queries and calculate how much each of them adds stones, so the complexity is: O (K * M), which fits within the given 2 seconds well. A faster solution with complexity O(N + M + K) is as follows: we will keep in mind two variables: a – how many items should be added now to the cell, v - how much should change a next step. So problem is to update the value of a and v so that a equaled to the number of stones in the cell after all the operations, and v – to how much a increases during the transition to the next cell. Then the problem will be reduced to that you need to properly update a and v, which is not very difficult to do, for example if there is a request (x, y, z) – then in the cell x you need to add x to a and add 1 to v, since with each next cell the number of stones for some staircase will increase by 1. Similarly, after the cell y is passed you need to subtract 1 from v and pick up from “a” the current number of stones subquery. If you save all such pairs of queries in a single array and it's possible to calculate everything in one cycle.</span></span><span style=\"color: black;\"></span></font></p><p><font face=\"arial\" size=\"2\"></font></p><h3 style=\"font-family: Verdana;line-height: normal;font-size: medium;\"><font face=\"arial\" size=\"2\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem C</span></font></font></h3><p style=\"color: black;font-weight: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">First, let's count how many there are arrays in which each successive element starting from the second one is no less than the previous one. To do this quickly, let’s take a piece of squared with height of one square and the length of N*2 - 1 square, then select N-1 squares and put crosses in them - let it encode some array, let the number of blank cells from the beginning of the array before the first cross be equal to the number of ones in the array, the number of blank cells from the first cross to the second – to the number of 2 in the array, and so on. It is easy to see that the number of empty cells will be equal to N * 2-1 - (N-1) = N. It turns out that each paper encodes an array which suits us, and moreover all the possible arrays can be encoded using such paper. There is exactly C (N * 2-1, N) different pieces of paper (the binomial coefficient of N * 2-1 to N). This number can be calculated by formula with factorials, the only difficulty is division. Since the module was prime - it was possible to calculate the inverse number in the field for the module and replace division by multiplication. So we get the number of non-decreasing sequences, respectively have the same number of non-increasing, we just need to take away those who were represented in both array sets, but they are just arrays with a similar number like {1,1,1,...,1} or {4,4,...,4,4} just subtract n.</span></span><span style=\"font-size: 9.0pt;font-family: Arial , sans-serif;color: black;\"></span></font></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem D</span></font></h3><p style=\"color: black;font-family: Arial , sans-serif;font-size: 12.0px;line-height: 20.0px;font-weight: normal;\"><span><span lang=\"RU\" style=\"font-family: Arial , sans-serif;color: black;\"></span></span></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">Let's see, if there is no occupied cells, then it is not difficult to calculate the answer - the answer is a sum of Manhattan distances, taking into account the fact that the Manhattan distance can be divided: first we can calculate the distance of one coordinate and then of another one and then just to sum up, so the answer is not difficult to find. What do we have when there are occupied cells? If the cell from which we seek the distance does not lie on the same horizontal or vertical with occupied cells – then it absolutely does not affect the difficulty of accessing the rest of the cells:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-1.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">This happens due to the fact that in each cell from the previous distance front (the distance to the set of cells with maximum distance from the start cell, the fronts form a diamond as you can see in the picture or from the Manhattan distance formula) there are two ways how to get to the cell, we take into account the rule that no two cells can be adjacent (either diagonally or vertically or horizontally), it turns out that such a cell does not interfere with us. But a close look at the picture brings to mind the obvious: it is the cell which is located on the same vertical / horizontal that has only one neighbor from the previous front, let’s see what happens in such case:</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-2.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><font face=\"Arial, sans-serif\"><span style=\"font-family: arial;font-size: small;\">All the cells after occupied one starts "to lag" at 2 in distance, but more importantly, that changed the front! Now (with the upper side of the front) are 2 cells for which the transition from the previous front is unique, and as a consequence there are two cells meeting of which will produce a new segment of a late cells, and the angle of the front will change again. Since we are only interested in one side of its expansion (on the other hand there can not be occupied cells by the condition) so we can assume that it was expand from the start cell:</span><br /></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"><img src=\"https://vnevidomy.narod2.ru/images/d-3.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /><br /></p><p style=\"font-weight: normal;line-height: normal;\"><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">It turns out that you can count how many cells will be "delayed", especially considering that the lag always equals to two. For each direction, you can choose each occupied cell and check in the left and right directions for adjacent cells series, and add delay for interval of free cell before occupied cell (in the current direction). It is possible to calculate such delays with complexity: square of the number of occupied cells (it is not greater than min(N, M)). The rest is details. You need to compute all Manhattan distances, taking into account the existence of occupied cells. To do this, first calculate the sum of distances for an empty field, then for each occupied cell calculate the distance to all the others - subtract it twice, as the extra distance is subtracted for the first time when we got out of this cell and for the second time when takes away from all other cells to the given one. But in this case we will take away twice the distance between two occupied cells - so we’ll have to add them (the complexity is also a square). A total complexity of solution is O (K ^ 2) where K is the number of occupied cells.</span></span><span style=\"font-size: 13.5pt;font-family: Verdana , sans-serif;color: black;\"></span></font></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><p style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></p><h3 style=\"font-family: Verdana;font-weight: normal;line-height: normal;font-size: medium;\"></h3><h3 style=\"font-size: medium;font-family: Verdana;line-height: normal;\"><font face=\"Arial, sans-serif\"><span style=\"font-size: 14.0px;line-height: 20.0px;\">Problem E</span></font></h3><h3 style=\"font-weight: normal;\"><span style=\"font-weight: normal;\"><p><font face=\"arial\" size=\"2\"></font></p><p style=\"margin-top: 12.0pt;margin-right: 0.0in;margin-bottom: 12.0pt;margin-left: 0.0in;line-height: 15.0pt;\"><font face=\"arial\" size=\"2\"><span><span style=\"font-family: Arial , sans-serif;color: black;\">The task turned out to be very difficult as it was planned. First remove all the deleted cells - let's see how changes the number of accessible cells with the increase of the new moves. First, the changes do not appear stable, but at some point we see a figure which won’t to change the form anymore and will only expand, it is obvious that the figure is two-dimensional, therefore the growth of its “area” is a quadratic function, in fact, a simple check shows that with each new turn the number of cells increases by the number of new cells opened with previous turn + 28, so after a certain point, you can simply take the sum of an arithmetic progression. The case with the deleted cells is similar. In general, there are several possible options - either occupied cells block further penetration of the horse or not, in the first case bfs is simply enough to find solutions, in the second one the story is the same: over time, when the figure "becomes balanced", the number of new opened cells satisfies the same rule "prev +28" . Moreover, because of restrictions of the coordinates of the deleted cells (-10 <= x, y <= 10) this happens fairly quickly. So, use usual bfs to balance figures, and after this use the sum of the arithmetic progression.</span></span><span style=\"color: black;\"></span></font></p></span></h3></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/57\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 53</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-296-1171\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"296\",\n blogEntryId: \"1171\",\n contestId: $(that).attr(\"data-contestId\"),\n resourceIds: $(that).attr(\"data-resourceIds\")\n }, function(json) { \n Codeforces.reloadAndShowMessageOrShowError(json, \"Contest detached\");\n });\n }, function () {}, \"Yes\", \"No\");\n });\n });\n</script>\r\n \r\n\r\n <div style=\"font-size: 1.1rem;line-height: 11px;\">\r\n <img style=\"vertical-align: middle;\" src=\"//codeforces.org/s/81027/images/blog/tags.png\" title=\"Tags\" alt=\"Tags\"/>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces</a>,\r\n </span>\r\n <span style=\"padding: 0 0.35em;\">\r\n <a href=\"/search?query=codeforces+round+53\" class=\"tag notice\" style=\"text-decoration: none;\">codeforces round 53</a>\r\n </span>\r\n </div>\r\n\r\n\n <div class=\"roundbox meta borderTopRound borderBottomRound\" style=\"\">\n <div class=\"left-meta\">\r\n <ul>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-up-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/voteup.png\"\n alt=\"Vote: I like it\" title=\"Vote: I like it\"\n /></a>\n\n\n</li>\r\n <li style=\"line-height: 1.6em;\">\n\n \n <span title=\"Topic rating\" style='font-size:larger;position:relative;bottom:1px;font-weight:bold;color:green'>+24</span>\n \n</li>\r\n <li style=\"line-height: 1.6em;\"> <a href=\"#\" class=\"topic-vote-down-1171\"><img style=\"vertical-align:middle;position:relative;top:-0.2em\" src=\"//codeforces.org/s/81027/images/actions/votedown.png\"\n alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"\n /></a>\n\n\n</li>\r\n </ul>\r\n </div>\r\n\r\n\r\n <span style=\"position: relative; line-height: 1.65em; top: 0.75rem; left: 0.8em;\">\r\n </span>\r\n\r\n <div class=\"right-meta\">\r\n <ul>\r\n <li> <a href=\"/profile/nevidomy\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/user_16x16.png\"\n alt=\"Author\" title=\"Author\"\n /></a>\n\n\n <a href=\"/profile/nevidomy\">\n nevidomy\n </a>\n</li>\r\n <li> <img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/date_16x16.png\"\n alt=\"Publication date\" title=\"Publication date\"\n />\n\n\n \n <span class=\"format-humantime\" title=\"Jan/26/2011 00:26\">13 years ago</span>\n \n</li>\r\n <li> <a href=\"/blog/entry/1171#comments\"><img style=\"vertical-align:middle;position:relative;top:-1px\" src=\"//codeforces.org/s/81027/images/blog/comments_16x16.png\"\n alt=\"Comments\" title=\"Comments\"\n /></a>\n\n\n <a href=\"/blog/entry/1171#comments\">\n 15\n </a>\n</li>\r\n </ul>\r\n </div>\r\n\r\n <br style=\"clear:both;\"/>\r\n </div>\n\r\n\r\n<style type=\"text/css\">\r\n .comments .title {\r\n float: left;\r\n }\r\n\r\n .comments .comments-actions-div {\r\n float: right;\r\n margin-top: 3rem;\r\n margin-right: 0.5em;\r\n }\r\n\r\n .comments .comments-actions-div .separator {\r\n margin: 0 1rem;\r\n }\r\n\r\n .comments label.show-archived {\r\n }\r\n\r\n .comments label.show-archived, .comments label.show-archived * {\r\n font-size: 1.4rem !important;\r\n color: black !important;\r\n /*position: relative !important;*/\r\n /*bottom: 0.4rem !important;*/\r\n }\r\n\r\n .comments label.show-archived input {\r\n height: 1.4rem !important;\r\n width: 1.4rem !important;\r\n position: relative;\r\n top: 0.25rem;\r\n }\r\n\r\n .new-root-comment {\r\n font-size: 1.4rem !important;\r\n }\r\n</style>\r\n\r\n <div class=\"comments\" commentableId=\"1181\">\r\n <div style=\"display: flow-root\">\r\n <div class=\"title\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/comments-48x48.png\" alt=\"Comments\" title=\"Comments\"\r\n style=\"position:relative;top:0.6em;\"/>\r\n <a name=\"comments\">Comments (12)</a>\r\n\r\n </div>\r\n <div class=\"comments-actions-div\">\r\n <label class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20840\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/lyrics\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3858/avatar/29787cdba9b12888.jpg'/> </a>\n <div><a href=\"/profile/lyrics\" title=\"Expert lyrics\" class=\"rated-user user-blue\">lyrics</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 04:43\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20840\" href=\"?#comment-20840\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20840\" revisionCount=\"5\" revision=\"5\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">5</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20840\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"3858\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20840\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">the translation is a bit difficult to understand...= =<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20840 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20840 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20840\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20854\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RosyIsh\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/2476/avatar/89dff08f92b47321.jpg'/> </a>\n <div><a href=\"/profile/RosyIsh\" title=\"Expert RosyIsh\" class=\"rated-user user-blue\">RosyIsh</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 09:53\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20854\" href=\"?#comment-20854\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20854\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"2476\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20854\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div><div>I can't clearly understand the solution to B here.</div><div>I submitted an O(M*K) in the contest which passed.</div><div><br /></div><div>Now, I tried another approach using fenwick tree , complexity O(M log N + K log N) which passed too. Here's a link to see the code : <a href=\"http://pastebin.com/SAeFbdcG\">http://pastebin.com/SAeFbdcG</a></div><div><br /></div><div>Is this what is intended in the tutorial or a much simpler solution ?<br /></div></div><div><br /></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20854 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20854 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20854\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20859\" commentParentId=\"20854\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/RedAnt\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/550/avatar/a60953c6a6e6562a.jpg'/> </a>\n <div><a href=\"/profile/RedAnt\" title=\"Expert RedAnt\" class=\"rated-user user-blue\">RedAnt</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 11:19\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20859\" href=\"?#comment-20859\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20854\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20859\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20859\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"550\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20859\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">As constraints for n are small, we can mark values on the number line and update the current values, as we walk through. Here is a O(m+k+n) <a href=\"http://www.ideone.com/CcTUY\">http://www.ideone.com/CcTUY</a></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20859 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20859 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20859\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20874\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/the_saint\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/11054/avatar/9d5201d3625a6201.jpg'/> </a>\n <div><a href=\"/profile/the_saint\" title=\"Candidate Master the_saint\" class=\"rated-user user-violet\">the_saint</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:33\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20874\" href=\"?#comment-20874\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20874\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"11054\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20874\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">I'm not that good at maths and although I knew little Fermat's theorem before, using it in that way was something new to me. <div><br /></div><div>But what if the module wasn't a primer number? In the contest I used dp to calculate the combination and my approach isn't depended by the module. I'm curious if there is a way (maybe involving math) different than this if the module isn't prime?</div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20874 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20874 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20874\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20875\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/ant.ermilov\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/452/avatar/26a5367a89736db7.jpg'/> </a>\n <div><a href=\"/profile/ant.ermilov\" title=\"Expert ant.ermilov\" class=\"rated-user user-blue\">ant.ermilov</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 13:46\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20875\" href=\"?#comment-20875\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20875\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"452\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20875\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Theoretically you can use <a href=\"https://en.wikipedia.org/wiki/Chinese_remainder_theorem\">Chinese remainder theorem</a> on prime factorization of module and then restore answer.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20875 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20875 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20875\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20893\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Urbanowicz\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/Urbanowicz\" title=\"Expert Urbanowicz\" class=\"rated-user user-blue\">Urbanowicz</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 17:26\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20893\" href=\"?#comment-20893\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20893\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20893\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"3\"\r\n data-commentUserId=\"11366\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+3</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20893\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\"><a>Euler's totient theorem</a> is a generalization of Fermat's one and works for any module. Also you can solve <span class=\"tex-span\"><i>ax</i> ≡ 1</span> (mod b) equation by solving its equivalent Diophantine equation <span class=\"tex-span\"><i>ax</i> + <i>by</i> = 1</span> with extended Euclidean algorithm.</div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20893 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20893 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20893\">\r\n </ul>\r\n</div>\r\n</li>\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20933\" commentParentId=\"20874\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/havaliza\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/402/avatar/f5a24cdc4359b26.jpg'/> </a>\n <div><a href=\"/profile/havaliza\" title=\"Candidate Master havaliza\" class=\"rated-user user-violet\">havaliza</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 23:04\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20933\" href=\"?#comment-20933\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20874\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20933\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20933\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"402\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20933\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">I didn't use any thing about prime module in my solution. For all prime numbers between 1 and 2n-1 I just computed their power in C(2n-1, n) and then multiplied the result with it. Computing the power was easy, like computing the number of first zero digits of n!. It ran in 130ms.<br />Here is my code: http://pastebin.com/Xieb5PuP<br /></div> </div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20933 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20933 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20933\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20922\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/26/2011 21:30\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20922\" href=\"?#comment-20922\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n <span style=\"\" commentId=\"20922\" revisionCount=\"2\" revision=\"2\">\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;color:#bebebe;\" class=\"leftRevision\">←</a>\r\n Rev. <span class=\"revision\">2</span>\r\n <a href=\"#\" style=\"text-decoration:none;font-size:1.4rem;visibility:hidden;color:#bebebe;\" class=\"rightRevision\">→</a>\r\n </span>\r\n \r\n\r\n<span commentid=\"20922\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20922\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><div class=\"from-renderer\"><div class=\"from-renderer\">Thanks for the tutorial. But I cant understand the explanation of problem C. The explanation is very confusing :(<span style=\"font-family: arial;line-height: normal;font-size: small;\"><br /></span></div></div></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20922 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20922 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20922\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20952\" commentParentId=\"20922\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 01:57\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20952\" href=\"?#comment-20952\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20922\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20952\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"1\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+1</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20952\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Try <a href=\"//codeforces.com/blog/entry/1169#comment-20773\">this one</a>.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20952 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20952 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20952\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20977\" commentParentId=\"20952\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/Tahlil\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/3050/avatar/810769a816e5c94f.jpg'/> </a>\n <div><a href=\"/profile/Tahlil\" title=\"Specialist Tahlil\" class=\"rated-user user-cyan\">Tahlil</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 13:03\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20977\" href=\"?#comment-20977\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20952\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20977\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"3050\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20977\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Thank you very much :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20977 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20977 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20977\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20989\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/looc\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/looc\" title=\"Unrated, looc\" class=\"rated-user user-black\">looc</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 17:50\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20989\" href=\"?#comment-20989\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20989\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"12456\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20989\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">In problem D, i am facing a tough time in finding the sum of manhattan distances in O(max(n^2 ,m^2)). Can someone give me a hint? :)</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20989 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20989 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20989\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"20991\" commentParentId=\"20989\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/slycelote\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/slycelote\" title=\"Master slycelote\" class=\"rated-user user-orange\">slycelote</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jan/27/2011 19:32\">13 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-20991\" href=\"?#comment-20991\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-20989\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"20991\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"4\"\r\n data-commentUserId=\"703\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+4</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-20991\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">The sum of Manhattan distances over all cells: <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7a81e71722ed9132468b80c15f6e451c5f2b85f6.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/4ded835a280e330bc0ce060e978554a1454375f4.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" /> = <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/7409ac8b1c963c0a9884ac2a550fab38702d8302.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />.<br /><br />Now we need to subtract the sum of Manhattan distances with occupied cells. Suppose <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span> is one of occupied cells, then <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/917e8a7b9262bb634b6460dc2199659511615898.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />. Since there are at most <span class=\"tex-span\"><i>max</i>(<i>n</i>, <i>m</i>)</span> occupied cells, we can just sum over all <span class=\"tex-span\">(<i>x</i>, <i>y</i>)</span>.<br /><br />Finally, the pairs of occupied cells were subtracted twice and we need to add them back. It's <span class=\"tex-span\"><i>O</i>(<i>max</i>(<i>n</i><sup class=\"upper-index\">2</sup>, <i>m</i><sup class=\"upper-index\">2</sup>))</span> as well.<br /><br />And don't forget that the order of cells matters, so for example the sums in the second paragraph above need to be multiplied by 2.</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-20991 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-20991 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-20991\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1181\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; top: 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{document.onreadystatechange = prev;handler();}};}})();</script></body>\n</html>\n"}}},{"rowIdx":299,"cells":{"problem_id":{"kind":"string","value":"58A"},"contest":{"kind":"string","value":"58"},"problem":{"kind":"string","value":"A"},"lang":{"kind":"string","value":"en"},"problem_title":{"kind":"string","value":"A. Chat room"},"problem_statement":{"kind":"string","value":"<div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Chat room</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya has recently learned to type and log on to the Internet. He immediately entered a chat room and decided to say hello to everybody. Vasya typed the word <span class=\"tex-span\"><i>s</i></span>. It is considered that Vasya managed to say hello if several letters can be deleted from the typed word so that it resulted in the word \"<span class=\"tex-font-style-tt\">hello</span>\". For example, if Vasya types the word \"<span class=\"tex-font-style-tt\">ahhellllloou</span>\", it will be considered that he said hello, and if he types \"<span class=\"tex-font-style-tt\">hlelo</span>\", it will be considered that Vasya got misunderstood and he didn't manage to say hello. Determine whether Vasya managed to say hello by the given word <span class=\"tex-span\"><i>s</i></span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first and only line contains the word <span class=\"tex-span\"><i>s</i></span>, which Vasya typed. This word consisits of small Latin letters, its length is no less that 1 and no more than 100 letters.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If Vasya managed to say hello, print \"<span class=\"tex-font-style-tt\">YES</span>\", otherwise print \"<span class=\"tex-font-style-tt\">NO</span>\".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>ahhellllloou<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br/></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>hlelo<br/></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br/></pre></div></div></div></div>"},"page":{"kind":"string","value":"\r\n<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01//EN\">\n<html lang=\"en\">\n<head>\n <meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\">\n <meta name=\"X-Csrf-Token\" content=\"c41dcfdcc6b99ad89691851b4bb3e8fc\"/>\n <meta id=\"viewport\" name=\"viewport\" content=\"width=device-width, initial-scale=0.01\"/>\n\n\n <script type=\"text/javascript\" src=\"//codeforces.org/s/73366/js/jquery-1.8.3.js\"></script>\n <script type=\"application/javascript\">\n window.locale = \"en\";\n window.standaloneContest = false;\n function adjustViewport() {\n var screenWidthPx = Math.min($(window).width(), window.screen.width);\n var siteWidthPx = 1100; // min width of site\n var ratio = Math.min(screenWidthPx / siteWidthPx, 1.0);\n var viewport = \"width=device-width, initial-scale=\" + ratio;\n $('#viewport').attr('content', viewport);\n var style = $('<style>html * { max-height: 1000000px; }</style>');\n $('html > head').append(style);\n }\n\n if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry/i.test(navigator.userAgent) ) {\n adjustViewport();\n }\n\n /* Protection against trailing dot in domain. */\n let hostLength = window.location.host.length;\n if (hostLength > 1 && window.location.host[hostLength - 1] === '.') {\n window.location = window.location.protocol + \"//\" + window.location.host.substring(0, hostLength - 1);\n }\n </script>\n <meta http-equiv=\"pragma\" content=\"no-cache\">\n <meta http-equiv=\"expires\" content=\"-1\">\n <meta http-equiv=\"profileName\" content=\"j3\">\n <meta name=\"google-site-verification\" content=\"OTd2dN5x4nS4OPknPI9JFg36fKxjqY0i1PSfFPv_J90\"/>\n <meta property=\"fb:admins\" content=\"100001352546622\" />\n <meta property=\"og:image\" content=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <link rel=\"image_src\" href=\"//codeforces.org/s/73366/images/codeforces-sponsored-by-ton.png\" />\n <meta property=\"og:title\" content=\"Problem - A - Codeforces\"/>\n <meta property=\"og:description\" content=\"\"/>\n \n <meta property=\"og:site_name\" content=\"Codeforces\"/>\n \n \n \n <meta name=\"cc\" content=\"3e49fd6c8089e4b7cfc6fda3fb990ebb896601af\"/>\n \n \n <meta name=\"utc_offset\" content=\"+03:00\"/>\n <meta name=\"verify-reformal\" content=\"f56f99fd7e087fb6ccb48ef2\" />\n <title>Problem - A - Codeforces</title>\n <meta name=\"description\" content=\"Codeforces. 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Just register for practice and you will be able to submit solutions.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"\" method=\"post\"><input type='hidden' name='csrf_token' value='c41dcfdcc6b99ad89691851b4bb3e8fc'/>\r\n <input type=\"hidden\" name=\"action\" value=\"registerForPractice\"/>\r\n <input type=\"submit\" name=\"submit\" value=\"Register for practice\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div> \r\n</div>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox ContestVirtualFrame borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Virtual participation <i class=\"sidebar-caption-icon las la-angle-down\"></i>\r\n\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\" \"\r\n\r\n data-page-url=\"/data/sidebarFrames\"\r\n\r\n>\r\n <div style=\"margin:1em;font-size:0.8em;\">\r\n Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.\n\nIf you've seen these problems, a virtual contest is not for you - solve these problems in the archive.\n\nIf you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.\n\nNever use someone else's code, read the tutorials or communicate with other person during a virtual contest.\r\n </div>\r\n\r\n <div style=\"text-align:center;margin:1em;\">\r\n <form action=\"/contest/58/virtual\" method=\"get\">\r\n <input type=\"submit\" name=\"submit\" value=\"Start virtual contest\" style=\"padding:0 0.5em;\">\r\n </form>\r\n </div>\r\n</div>\r\n <script>\r\n $(function () {\r\n $(\".ContestVirtualFrame .sidebar-caption-icon\").click(function() {\r\n $(this).toggleClass(\"la-angle-down la-angle-right\");\r\n const $target = $(this).parent().next();\r\n $target.toggle();\r\n const dataPageUrl = $target.attr(\"data-page-url\");\r\n const collapsed = $(this).hasClass(\"la-angle-right\");\r\n const params = {\r\n action: \"setCollapsed\",\r\n sidebarFrameSimpleClassName: \"ContestVirtualFrame\",\r\n collapsed\r\n };\r\n $.each($target[0].attributes, function(i, a) {\r\n const name = a.name;\r\n if (name.startsWith(\"data-extra-key-\")) {\r\n const key = a.value;\r\n const keyIndex = parseInt(name.substring(\"data-extra-key-\".length));\r\n const value = $target.attr(\"data-extra-value-\" + keyIndex);\r\n params[key] = value;\r\n }\r\n });\r\n $.post(dataPageUrl, params, function (result) {\r\n if (result[\"success\"] !== \"true\") {\r\n Codeforces.showMessage(\"Failed to save collapsed state.\");\r\n }\r\n }, \"json\");\r\n return false;\r\n });\r\n })\r\n </script>\r\n </div>\n\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Problem tags\n <div class=\"top-links\">\n </div>\n </div>\n<div style=\"padding: 0.5em;\">\r\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Greedy algorithms\">\r\n greedy\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Prefix- and Z-functions, suffix structures, Knuth–Morris–Pratt algorithm, etc\">\r\n strings\r\n</span>\r\n </div>\n\n <div class=\"roundbox borderTopRound borderBottomRound\" style=\"margin:2px; padding:0 3px 2px 3px; background-color:#f0f0f0;float:left;\">\n<span class=\"tag-box\" style=\"font-size:1.2rem;\" title=\"Difficulty\">\r\n *1000\r\n</span>\r\n </div>\n <div style=\"clear:both;text-align:right;font-size:1.1rem;\">\r\n <span title=\"Please login into the Codeforces\" class=\"notice\">No tag edit access</span>\r\n </div>\r\n</div>\r\n </div>\n\r\n<form id=\"addTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='c41dcfdcc6b99ad89691851b4bb3e8fc'/>\r\n <input name=\"action\" type=\"hidden\" value=\"addTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"302\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<form id=\"removeTagForm\" action=\"/data/problemTags\" method=\"post\" style=\"display:none;\"><input type='hidden' name='csrf_token' value='c41dcfdcc6b99ad89691851b4bb3e8fc'/>\r\n <input name=\"action\" type=\"hidden\" value=\"removeTag\"/>\r\n <input name=\"problemId\" type=\"hidden\" value=\"302\"/>\r\n <input name=\"tagName\" type=\"hidden\" value=\"\"/>\r\n</form>\r\n\r\n<script type=\"text/javascript\">\r\n $(\".tag-box img\").click(function () {\r\n var tagName = $(this).attr(\"value\");\r\n Codeforces.confirm(\"Are you sure you want to remove this tag?\", function () {\r\n $(\"#removeTagForm input[name=tagName]\").val(tagName);\r\n $(\"#removeTagForm\").submit();\r\n }, function () {\r\n }, \"Yes\", \"No\");\r\n });\r\n\r\n $(\"#addTagLink\").click(function () {\r\n $(this).hide();\r\n $(\"#addTagLabel\").show();\r\n return false;\r\n });\r\n\r\n $(\"#addTagSelect\").change(function () {\r\n var tagName = $(this).val();\r\n if (tagName === \"\") {\r\n $(\"#addTagLabel\").hide();\r\n $(\"#addTagLink\").show();\r\n } else {\r\n $(\"#addTagForm input[name=tagName]\").val(tagName);\r\n $(\"#addTagForm\").submit();\r\n }\r\n });\r\n</script>\r\n\r\n<style type=\"text/css\">\r\n#new-resource-form tr td {\r\npadding-top: 0.5em;\r\n}\r\n#new-resource-form input:not([type=\"submit\"]) {\r\nfont-size: 0.8em;\r\n}\r\n#new-resource-form select {\r\nfont-size: 0.8em;\r\n}\r\n.new-resource-error {\r\nfont-size: 0.8em;\r\n}\r\n.resource-locale {\r\ncolor: #666;\r\nfont-family: Consolas, \"Andale Mono WT\", \"Andale Mono\", \"Lucida Console\", \"Lucida Sans Typewriter\", \"DejaVu Sans Mono\", \"Bitstream Vera Sans Mono\", \"Liberation Mono\", \"Nimbus Mono L\", Monaco, \"Courier New\", Courier, monospace;\r\n}\r\n</style>\r\n<div class=\"roundbox sidebox sidebar-menu borderTopRound \" style=\"\">\n<div class=\"caption titled\">→ Contest materials\n<div class=\"top-links\">\n</div>\n</div>\n<ul>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1197\" title=\"Codeforces Beta Round #54 (Div. 2)\" target=\"_blank\">Announcement</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"211:212\" resourceName=\"Announcement\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n<li>\r\n<span>\r\n<a href=\"/blog/entry/1771\" title=\"Codeforces Beta Round #54 (Div.2) - разбор A-D\" target=\"_blank\">Tutorial</a>\r\n</span>\r\n<span style=\"float: right;\">\r\n<img class=\"delete-resource-link\" resourceIds=\"848:849\" resourceName=\"Tutorial\"\r\nresourceManual=\"true\" src=\"//codeforces.org/s/73366/images/icons/close-10x10.png\"\r\nstyle=\"position: relative;bottom: -1px;left: 1px;cursor: pointer;\"/>\r\n</span>\r\n<div style=\"clear: both;\"></div>\r\n</li>\r\n</ul>\r\n</div></div>\n <div id=\"pageContent\" class=\"content-with-sidebar\">\n <div class=\"second-level-menu\">\r\n<ul class=\"second-level-menu-list\">\r\n <li class=\"current selectedLava\"><a\r\n href=\"/contest/58\">Problems</a></li>\r\n <li><a\r\n href=\"/contest/58/submit\">Submit Code</a></li>\r\n <li><a\r\n href=\"/contest/58/my\">My Submissions</a></li>\r\n <li><a\r\n href=\"/contest/58/status\">Status</a></li>\r\n <li><a\r\n href=\"/contest/58/hacks\">Hacks</a></li>\r\n <li><a\r\n href=\"/contest/58/room/1\">Room</a></li>\r\n <li><a\r\n href=\"/contest/58/standings\">Standings</a></li>\r\n <li><a\r\n href=\"/contest/58/customtest\">Custom Invocation</a></li>\r\n</ul>\r\n</div>\n\r\n <style>\r\n #facebox .content:has(.diff-popup) {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n }\r\n\r\n .testCaseMarker {\r\n position: absolute;\r\n font-weight: bold;\r\n font-size: 1rem;\r\n }\r\n\r\n .diff-popup {\r\n width: 90vw;\r\n max-width: 120rem !important;\r\n display: none;\r\n overflow: auto;\r\n }\r\n\r\n .input-output-copier {\r\n font-size: 1.2rem;\r\n float: right;\r\n color: #888 !important;\r\n cursor: pointer;\r\n border: 1px solid rgb(185, 185, 185);\r\n padding: 3px;\r\n margin: 1px;\r\n line-height: 1.1rem;\r\n text-transform: none;\r\n }\r\n\r\n .input-output-copier:hover {\r\n background-color: #def;\r\n }\r\n\r\n .test-explanation textarea {\r\n width: 100%;\r\n height: 1.5em;\r\n }\r\n\r\n .pending-submission-message {\r\n color: darkorange !important;\r\n }\r\n </style>\r\n <script>\r\n const OPENING_SPACE = String.fromCharCode(1001);\r\n const CLOSING_SPACE = String.fromCharCode(1002);\r\n\r\n const nodeToText = function (node, pre) {\r\n let result = [];\r\n\r\n if 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|| c === '.' || c === ';' || c === ')' || c === ' ';\r\n }\r\n\r\n const convertStatementToText = function(statmentNode) {\r\n const text = nodeToText(statmentNode, false).join(\"\").replace(/ +/g, \" \").replace(/\\n\\n+/g, \"\\n\\n\");\r\n let result = [];\r\n for (let i = 0; i < text.length; i++) {\r\n const c = text.charAt(i);\r\n if (c === OPENING_SPACE) {\r\n if (!((i > 0 && text.charAt(i - 1) === '(') || (result.length > 0 && result[result.length - 1] === ' '))) {\r\n result.push('+');\r\n }\r\n } else if (c === CLOSING_SPACE) {\r\n if (!(i + 1 < text.length && isSpecial(text.charAt(i + 1)))) {\r\n result.push('-');\r\n }\r\n } else {\r\n result.push(c);\r\n }\r\n }\r\n return result.join(\"\").split(\"\\n\").map(value => value.trim()).join(\"\\n\");\r\n };\r\n </script>\r\n <div class=\"diff-popup\">\r\n </div>\r\n\r\n<div class=\"problemindexholder\" problemindex=\"A\" data-uuid=\"ps_dab6a67212da3b5a29881884b5c9e0b70cc833d9\">\r\n <div style=\"display: none; margin:1em 0;text-align: center; position: relative;\" class=\"alert alert-info diff-notifier\">\r\n <div>The problem statement has recently been changed. <a class=\"view-changes\" href=\"#\">View the changes.</a></div>\r\n <span class=\"diff-notifier-close\" style=\"position: absolute; top: 0.2em; right: 0.3em; cursor: pointer; font-size: 1.4em;\">×</span>\r\n </div>\r\n <div class=\"ttypography\"><div class=\"problem-statement\"><div class=\"header\"><div class=\"title\">A. Chat room</div><div class=\"time-limit\"><div class=\"property-title\">time limit per test</div>1 second</div><div class=\"memory-limit\"><div class=\"property-title\">memory limit per test</div>256 megabytes</div><div class=\"input-file\"><div class=\"property-title\">input</div>standard input</div><div class=\"output-file\"><div class=\"property-title\">output</div>standard output</div></div><div><p>Vasya has recently learned to type and log on to the Internet. He immediately entered a chat room and decided to say hello to everybody. Vasya typed the word <span class=\"tex-span\"><i>s</i></span>. It is considered that Vasya managed to say hello if several letters can be deleted from the typed word so that it resulted in the word "<span class=\"tex-font-style-tt\">hello</span>". For example, if Vasya types the word "<span class=\"tex-font-style-tt\">ahhellllloou</span>", it will be considered that he said hello, and if he types "<span class=\"tex-font-style-tt\">hlelo</span>", it will be considered that Vasya got misunderstood and he didn't manage to say hello. Determine whether Vasya managed to say hello by the given word <span class=\"tex-span\"><i>s</i></span>.</p></div><div class=\"input-specification\"><div class=\"section-title\">Input</div><p>The first and only line contains the word <span class=\"tex-span\"><i>s</i></span>, which Vasya typed. This word consisits of small Latin letters, its length is no less that 1 and no more than 100 letters.</p></div><div class=\"output-specification\"><div class=\"section-title\">Output</div><p>If Vasya managed to say hello, print "<span class=\"tex-font-style-tt\">YES</span>", otherwise print "<span class=\"tex-font-style-tt\">NO</span>".</p></div><div class=\"sample-tests\"><div class=\"section-title\">Examples</div><div class=\"sample-test\"><div class=\"input\"><div class=\"title\">Input</div><pre>ahhellllloou<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>YES<br /></pre></div><div class=\"input\"><div class=\"title\">Input</div><pre>hlelo<br /></pre></div><div class=\"output\"><div class=\"title\">Output</div><pre>NO<br /></pre></div></div></div></div></div>\r\n</div>\r\n\r\n <script>\r\n $(function () {\r\n Codeforces.addMathJaxListener(function () {\r\n let $problem = $(\"div[problemindex=A]\");\r\n let uuid = $problem.attr(\"data-uuid\");\r\n let 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class=\"legendary-user-first-letter\">c</span>nnfls_csy</a></td>\n<td class=\"\">3620</td>\n</tr>\n<tr>\n<td class=\"left dark\">7</td>\n<td class=\" dark\"><a href=\"/profile/-0.5\" title=\"Legendary Grandmaster -0.5\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">-</span>0.5</a></td>\n<td class=\" dark\">3545</td>\n</tr>\n<tr>\n<td class=\"left \">8</td>\n<td class=\"\"><a href=\"/profile/inaFSTream\" title=\"Legendary Grandmaster inaFSTream\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">i</span>naFSTream</a></td>\n<td class=\"\">3478</td>\n</tr>\n<tr>\n<td class=\"left dark\">9</td>\n<td class=\" dark\"><a href=\"/profile/fantasy\" title=\"Legendary Grandmaster fantasy\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">f</span>antasy</a></td>\n<td class=\" dark\">3468</td>\n</tr>\n<tr>\n<td class=\"left bottom\">10</td>\n<td class=\"bottom\"><a href=\"/profile/Rebelz\" title=\"Legendary Grandmaster Rebelz\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">R</span>ebelz</a></td>\n<td class=\"bottom\">3415</td>\n</tr>\n</tbody>\n</table>\n<div class=\"bottom-links\">\n<table style=\"width:100%;\">\n<tbody>\n<tr>\n<td style=\"text-align:left;\">\n<a href=\"/ratings/countries\">Countries</a> |\n<a href=\"/ratings/cities\">Cities</a> |\n<a href=\"/ratings/organizations\">Organizations</a>\n</td>\n<td style=\"text-align:right;\">\n<a href=\"/ratings\">View all →</a>\n</td>\n</tr>\n</tbody>\n</table>\n</div>\n</div><div class=\"roundbox sidebox top-contributed borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Top contributors\n <div class=\"top-links\">\n </div>\n </div>\n <table class=\"rtable \">\n <tbody>\n <tr>\n <th class=\"left\" style=\"width:2.25em;\">#</th>\n <th class=\"\">User</th>\n <th class=\"\" style=\"width:5em;\">Contrib.</th>\n </tr>\n <tr>\n <td class=\"left dark\">1</td>\n <td class=\" dark\"><a href=\"/profile/adamant\" title=\"Grandmaster adamant\" class=\"rated-user user-red\">adamant</a></td>\n <td class=\" dark\">178</td>\n </tr>\n <tr>\n <td class=\"left \">2</td>\n <td class=\"\"><a href=\"/profile/awoo\" title=\"Master awoo\" class=\"rated-user user-orange\">awoo</a></td>\n <td class=\"\">167</td>\n </tr>\n <tr>\n <td class=\"left dark\">3</td>\n <td class=\" dark\"><a href=\"/profile/BledDest\" title=\"International Grandmaster BledDest\" class=\"rated-user user-red\">BledDest</a></td>\n <td class=\" dark\">165</td>\n </tr>\n <tr>\n <td class=\"left \">4</td>\n <td class=\"\"><a href=\"/profile/Um_nik\" title=\"Legendary Grandmaster Um_nik\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">U</span>m_nik</a></td>\n <td class=\"\">163</td>\n </tr>\n <tr>\n <td class=\"left dark\">5</td>\n <td class=\" dark\"><a href=\"/profile/maroonrk\" title=\"Legendary Grandmaster maroonrk\" class=\"rated-user user-legendary\"><span class=\"legendary-user-first-letter\">m</span>aroonrk</a></td>\n <td class=\" dark\">162</td>\n </tr>\n <tr>\n <td class=\"left \">6</td>\n <td class=\"\"><a href=\"/profile/SecondThread\" title=\"Master SecondThread\" class=\"rated-user user-orange\">SecondThread</a></td>\n <td class=\"\">160</td>\n </tr>\n <tr>\n <td class=\"left dark\">7</td>\n <td class=\" dark\"><a href=\"/profile/nor\" title=\"Master nor\" class=\"rated-user user-orange\">nor</a></td>\n <td class=\" dark\">158</td>\n </tr>\n <tr>\n <td class=\"left \">8</td>\n <td class=\"\"><a href=\"/profile/-is-this-fft-\" title=\"Grandmaster -is-this-fft-\" class=\"rated-user user-red\">-is-this-fft-</a></td>\n <td class=\"\">152</td>\n </tr>\n <tr>\n <td class=\"left dark\">9</td>\n <td class=\" dark\"><a href=\"/profile/kostka\" title=\"International Grandmaster kostka\" class=\"rated-user user-red\">kostka</a></td>\n <td class=\" dark\">145</td>\n </tr>\n <tr>\n <td class=\"left bottom\">10</td>\n <td class=\"bottom\"><a href=\"/profile/TheScrasse\" title=\"International Grandmaster TheScrasse\" class=\"rated-user user-red\">TheScrasse</a></td>\n <td class=\"bottom\">144</td>\n </tr>\n </tbody>\n </table>\n <div class=\"bottom-links\">\n <table style=\"width:100%;\">\n <tbody>\n <tr>\n <td style=\"text-align:left;\">\n </td>\n <td style=\"text-align:right;\">\n <a href=\"/top-contributed\">View all →</a>\n </td>\n </tr>\n </tbody>\n </table>\n </div>\n </div>\n\r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n });\n </script>\r\n\r\n\n <div class=\"roundbox sidebox borderTopRound \" style=\"\">\n <div class=\"caption titled\">→ Find user\n <div class=\"top-links\">\n </div>\n </div>\n <form class=\"handleForm\" method=\"post\"><input type='hidden' name='csrf_token' value='37b1edf29e42b9090754c866e4781651'/>\r\n <div style=\"padding:1em;text-align:right;\">\r\n <label style=\"padding-right:1em;\">Handle:\r\n <input style=\"width:12em;\" type=\"text\" class=\"handleBox\"/>\r\n 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class=\"rated-user user-red\">yeputons</a>,\r\n <span class=\"format-humantime\" title=\"Apr/20/2011 14:44\">12 years ago</span>,\r\n translation,\r\n <img style=\"position: relative;top: 5px;\" src=\"//codeforces.org/s/81027/images/flags/24/gb.png\" alt=\"In English\" title=\"In English\"/>\r\n\r\n\r\n\r\n <span style=\"position:absolute;right:0;top:0.05em;margin-right:1em;display:inline;font-size:0.75em;\">\r\n <div style=\"margin-top:0.25em;\">\r\n </div>\r\n </span>\r\n </div>\r\n\r\n <div class=\"content\">\r\n <div class=\"ttypography\"><div align=\"center\"><b>Problem A. Chat room<br /></b><div align=\"left\">Solution is greedy algorithm. The first thing we do is find in our string the first letter 'h'. Then we find letter 'e' which is righter that found 'h'. If we find the whole word 'hello' in such way, obliviously, answer is YES.<br />Now let's prove that if answer exists, we find it. Let see on position of the 'h' in right answer. If we move it to the first 'h' in our string, nothing changes. But now we can say that our greedy algorithm correctly Now let's do such with the second letter, and so on.<br />We have greedy algorithm with work time O(n), where n - length of the input.<br /></div><br /><div align=\"left\"><div align=\"center\"><b>Problem B. Coins<br /></b><div align=\"left\">This problem also have greedy solution: we run down all number from 2 and greater and while denomination of the last added to answer coin is divisible by current number, we divide and increase answer.<br />You can prove correctness, if you take a look at prime factorizations of coins' denominations. In each next denomination each prime have less or equal power than the current one (it's equivalent to '<span class=\"tex-span\"><i>a</i></span> divide <span class=\"tex-span\"><i>b</i></span>'). Obliviously, if summary degree of primes decreases at least two (for example, we had number<span class=\"tex-span\"><i>a</i> = <i>x</i>· <i>y</i>· <i>z</i></span> (where <span class=\"tex-span\"><i>y</i>, <i>z</i> > 1</span>, and the current number is <span class=\"tex-span\"><i>b</i> = <i>x</i></span>), then we can add one more coin with demonitaion <span class=\"tex-span\"><i>a</i> > <i>c</i> = <i>x</i>· <i>y</i> > <i>b</i></span>. So, in the optimal answer sum of degrees decreasing at exactly one. Our greedy algorithm do exactly what it need.<br /><br /><div align=\"center\"><b>Problem C. Trees.</b><br /><div align=\"left\">The first thing we notice - beautiful sequence is can be determined with any member. The next thing - at least one tree will remain the same height. Prove: let's fix height of the first tree, and correct heights of all other ones. Obliviously, they all remain positive.<br />Solution with work time <span class=\"tex-span\"><i>O</i>(<i>n</i><sup class=\"upper-index\">2</sup>)</span>: we run down which tree we will fix, determine required height of the first tree and then relax answer.<br />This solution can be optimized to linear solution: if we don't touch some tree, we know the first element of sequence. Let's count for each possible element amount of trees, which have required height. It can be done with linear loop and the 'increment' operation on array. After that we just find value of the first element, for which amount of 'good' trees is maximal and output <span class=\"tex-span\"><i>n</i> - <i>x</i></span>, where <span class=\"tex-span\"><i>x</i></span> is this amount.<br /><div align=\"center\"><b><br />Problem D. Calendar</b><br /><div align=\"left\">We know, that all lines of calendar should have equal length, so we can find this length. It's just <img align=\"middle\" class=\"tex-formula\" src=\"https://espresso.codeforces.com/8cef3c7e80f6e681d72233b1fd7d682f2480a9a7.png\" style=\"max-width: 100.0%;max-height: 100.0%;\" />, where <span class=\"tex-span\"><i>suml</i></span> - summary length of all strings. Now let take a look at string, which will be the first one in our calendar. Obliviously, it's profitably to take string with maximal <span class=\"tex-span\"><i>s</i> + <i>d</i></span> (where <span class=\"tex-span\"><i>s</i></span> is our string and <span class=\"tex-span\"><i>d</i></span> - is character from input). Such string is unique otherwise we have two equal strings in input (as <span class=\"tex-span\"><i>d</i></span> is not contained in any string); Of cause, you should remember that if you fix the first string in a line, you fix length of the second one - it's required to have at least one such. Great, now we know the first string in our calendar. Now let's determine the second one. We know it's length, so we need just to take minimal string with such length.<br />We know one line, let's do similary with the second line and so on.<br /></div><div align=\"left\"><br /><div align=\"center\"><b>Problem E. Expression</b><br /><div align=\"left\">Under construction. The main idea is 3D dynamic with O(<span class=\"tex-span\">10<sup class=\"upper-index\">2</sup></span>) transition.<br /></div></div></div></div></div></div></div></div></div></div></div>\r\n\r\n </div>\r\n\r\n\r\n <div style=\"font-size: 1.1rem;line-height: 1.1rem;padding-bottom: 0.5em;\">\r\n <img src=\"//codeforces.org/s/81027/images/icons/paperclip-16x16.png\" style=\"vertical-align: middle;\"/> <span style=\"padding: 0 0.35em;\">Tutorial of <a href=\"/contest/58\" class=\"notice\" style=\"text-decoration: none;\">Codeforces Beta Round 54 (Div. 2)</a> </span>\r\n </div>\r\n \r\n <script type=\"text/javascript\">\n $(document).ready(function () {\n $(\".delete-resource-link-1484-1771\").click(function() {\n var that = this;\n Codeforces.confirm(\"Are you sure you want to detach a contest?\", function () {\n $.post(\"/data/blogAndContest\", {\n action: \"detachBlogFromContest\",\n blogId: \"1484\",\n blogEntryId: \"1771\",\n contestId: $(that).attr(\"data-contestId\"),\n 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class=\"show-archived\">\r\n <input type=\"checkbox\"\r\n class=\"show-archived-checkbox\" \n/>\r\n Show archived\r\n </label>\r\n <span class=\"separator\">|</span>\r\n <a href=\"#\" class=\"new-root-comment\"\r\n >Write comment?</a>\r\n </div>\r\n </div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"34253\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div class=\"avatar\">\n <a href=\"/profile/iman_MC\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/2447/avatar/b2ab3e48d7eb8c6.jpg'/> </a>\n <div><a href=\"/profile/iman_MC\" title=\"Pupil iman_MC\" class=\"rated-user user-green\">iman_MC</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Apr/23/2011 19:32\">12 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-34253\" href=\"?#comment-34253\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"34253\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"1\"\r\n data-commentUserId=\"2447\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+1</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-34253\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\">Really thanks for your Problem analysis .<br />I hope you complete this with write part E , good luck man :D</div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-34253 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-34253 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-34253\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"322835\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/1005032.maa2\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/no-avatar.jpg'/> </a>\n <div><a href=\"/profile/1005032.maa2\" title=\"Unrated, 1005032.maa2\" class=\"rated-user user-black\">1005032.maa2</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/28/2016 08:13\">7 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-322835\" href=\"?#comment-322835\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"322835\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"483783\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-322835\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Good Job Man</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-322835 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-322835 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-322835\">\r\n <li>\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"322890\" commentParentId=\"322835\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/Krktv\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/282980/avatar/a606aa5c5f801b89.jpg'/> </a>\n <div><a href=\"/profile/Krktv\" title=\"Candidate Master Krktv\" class=\"rated-user user-violet\">Krktv</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Oct/29/2016 01:56\">7 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-322890\" href=\"?#comment-322890\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\"><a title=\"Parent comment\" href=\"#comment-322835\" style=\"font-size:1.2em;\">^</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"322890\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"13\"\r\n data-commentUserId=\"282980\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:green;font-weight:bold;\">+13</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-322890\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>And necroposting is not a good job</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-322890 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-322890 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-322890\">\r\n </ul>\r\n</div>\r\n</li>\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"442334\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/berserker\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/492227/avatar/94b128dc6f18638b.jpg'/> </a>\n <div><a href=\"/profile/berserker\" title=\"Expert berserker\" class=\"rated-user user-blue\">berserker</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Jul/03/2018 20:57\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-442334\" href=\"?#comment-442334\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"442334\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"492227\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-442334\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>Can anyone give ideas about the DP solution for E.</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-442334 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-442334 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-442334\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"498855\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/Bekh\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/617670/avatar/3bb275557d131f6c.jpg'/> </a>\n <div><a href=\"/profile/Bekh\" title=\"Master Bekh\" class=\"rated-user user-orange\">Bekh</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Mar/13/2019 07:15\">5 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-498855\" href=\"?#comment-498855\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"498855\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"617670\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-498855\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>I'm 8 years late, but <a href=\"/contest/58/problem/C\" title=\"Codeforces Beta Round 54 (Div. 2)\">58C - Trees</a> has weak testcases. some solutions pass although they allow some tree heights to become non positive. </p><p>Case:<br /><code>10</code><br /><code>1 1 1 2 3 3 2 1 1 1</code> </p><p>Answer should be 8, (correct sequence: <code>1 2 3 4 5 5 4 3 2 1</code>) </p><p>Wrong answer is 4, (Assumes the correct sequence is: <code>-1 0 1 2 3 3 2 1 0 -1</code>)</p><p>Wrong submission: <a href=\"/contest/58/submission/51244937\" title=\"Submission 51244937 by Bekh\">51244937</a><br />Correct submission: <a href=\"/contest/58/submission/51245002\" title=\"Submission 51245002 by Bekh\">51245002</a></p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-498855 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-498855 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-498855\">\r\n </ul>\r\n</div>\r\n\r\n<div class=\"comment\">\r\n <table class=\"comment-table\"\r\n commentId=\"556210\" commentParentId=\"-1\">\r\n <tr>\r\n <td class=\"left\">\r\n <div style=\"position: absolute; left: 0;\" class=\"comment-indent-holder\">\r\n <div class=\"comment-no-indent\">\r\n <span>»</span>\r\n </div>\r\n </div>\r\n <div class=\"avatar\">\n <a href=\"/profile/Kylin_\" style=\"position: relative;\">\n<img src='https://userpic.codeforces.org/1193717/avatar/2296672a2c313067.jpg'/> </a>\n <div><a href=\"/profile/Kylin_\" title=\"Expert Kylin_\" class=\"rated-user user-blue\">Kylin_</a></div>\n </div>\n </td>\r\n <td class=\"right\">\r\n <div class=\"info\">\r\n \r\n <span class=\"item\"><span class=\"format-humantime\" title=\"Nov/05/2019 09:12\">4 years ago</span>,</span>\r\n <span class=\"item\"><a title=\"Link to comment\" name=\"comment-556210\" href=\"?#comment-556210\" style=\"font-size:1.2em;\">#</a></span>\r\n <span class=\"item\">|</span>\r\n <span style=\"position: relative; top: 2px;\">\r\n</span>\r\n <div style=\"position:absolute;right:0;top:0;\">\r\n \r\n\r\n<span commentid=\"556210\" class=\"CommentVoteFrame\"\r\n data-commentRating=\"0\"\r\n data-commentUserId=\"1193717\"\r\n style=\"position:relative;\"\r\n>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"1\" dd=\"x\"><img style=\"position:relative;top:3px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-voteup-blue.png\" alt=\"Vote: I like it\" title=\"Vote: I like it\"/></a>\r\n<span class=\"commentRating\"><span style=\"color:gray;font-weight:bold;\">0</span></span>\r\n<a href=\"#\" class=\"vote-for-comment\" voteDirection=\"-1\" dd=\"y\"><img style=\"position:relative;top:2px;opacity:0.35;\" src=\"//codeforces.org/s/81027/images/actions/comment-votedown-blue.png\" alt=\"Vote: I do not like it\" title=\"Vote: I do not like it\"/></a>\r\n</span>\r\n </div>\r\n </div>\r\n <div class=\"comment-content comment-content-556210\">\r\n <div class=\"moveup\">\r\n <div class=\"ttypography\"><p>So when we can get the solution of E?</p></div>\r\n </div>\r\n </div>\r\n <div class=\"reply info\">\r\n <a class=\"comment-556210 en false\" href=\"#\" style=\"text-decoration: none;\"><span class=\"arrow\">→</span></a>\r\n <a class=\"comment-556210 en false\" href=\"#\">Reply</a>\r\n </div>\r\n </td>\r\n </tr>\r\n </table>\r\n <ul class=\"comment-children comment-556210\">\r\n </ul>\r\n</div>\r\n <br/>\r\n\r\n<div id=\"editBox-1781\" style=\"width:50em;display:none;\">\r\n <div class=\"previewBody\" style=\"border: 1px solid #d4d4d4; margin-bottom: 0.5em; padding: 0.25em; display:none;\"> </div>\r\n <div style=\"width: 1px\"> </div>\r\n <div class=\"commentLocale\" style=\"position: relative; 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41A | 41 | A | en | A. Translation | <div class="problem-statement"><div class="header"><div class="title">A. Translation</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
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... | ["Implementation problems, programming technics, simulation", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["implementation", "strings", "*800"] | https://codeforces.com/blog/entry/1620 |
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41B | 41 | B | en | B. Martian Dollar | <div class="problem-statement"><div class="header"><div class="title">B. Martian Dollar</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
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<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="81e3641f6bb3c5d3a18c22e4de0d4527"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*1400"] | https://codeforces.com/blog/entry/1620 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="cc650a0d55dc2c8c1caa94e4a0cf0c67"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
41C | 41 | C | en | C. Email address | <div class="problem-statement"><div class="header"><div class="title">C. Email address</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6bd9de0b00c13d860f4763505160f75a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Parsing expression grammar", "Implementation problems, programming technics, simulation"] | ["expression parsing", "implementation", "*1300"] | https://codeforces.com/blog/entry/1620 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="cc650a0d55dc2c8c1caa94e4a0cf0c67"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
41D | 41 | D | en | D. Pawn | <div class="problem-statement"><div class="header"><div class="title">D. Pawn</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="67af228bb933a49533f98b3687c31732"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*1900"] | https://codeforces.com/blog/entry/1620 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="cc650a0d55dc2c8c1caa94e4a0cf0c67"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
41E | 41 | E | en | E. 3-cycles | <div class="problem-statement"><div class="header"><div class="title">E. 3-cycles</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bdbdeba366cbce79fe5097a1076d04c0"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Graphs", "Greedy algorithms"] | ["constructive algorithms", "graphs", "greedy", "*1900"] | https://codeforces.com/blog/entry/1620 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="cc650a0d55dc2c8c1caa94e4a0cf0c67"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
42A | 42 | A | en | A. Guilty — to the kitchen! | <div class="problem-statement"><div class="header"><div class="title">A. Guilty — to the kitchen!</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="743bc592311cc7665e23158e584db645"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Implementation problems, programming technics, simulation"] | ["greedy", "implementation", "*1400"] | https://codeforces.com/blog/entry/884 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9f75c8d4fa26670447f3b21157cc2656"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
42B | 42 | B | en | B. Game of chess unfinished | <div class="problem-statement"><div class="header"><div class="title">B. Game of chess unfinished</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="773570ee0d3d1476abb1f344bba2ea6b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1700"] | https://codeforces.com/blog/entry/884 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9f75c8d4fa26670447f3b21157cc2656"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
42C | 42 | C | en | C. Safe cracking | <div class="problem-statement"><div class="header"><div class="title">C. Safe cracking</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="75e8060fe8ecdfd803db3f279ef2ece2"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Constructive algorithms"] | ["brute force", "constructive algorithms", "*2200"] | https://codeforces.com/blog/entry/884 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9f75c8d4fa26670447f3b21157cc2656"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
42D | 42 | D | en | D. Strange town | <div class="problem-statement"><div class="header"><div class="title">D. Strange town</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="6e8987f3c0826383b469f67743dddd49"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Mathematics including integration, differential equations, etc"] | ["constructive algorithms", "math", "*2300"] | https://codeforces.com/blog/entry/884 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9f75c8d4fa26670447f3b21157cc2656"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
42E | 42 | E | en | E. Baldman and the military | <div class="problem-statement"><div class="header"><div class="title">E. Baldman and the military</div><div class="time-limit"><div class="property-title">time limit per test</div>4 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="744d8e1b55beab510c7d59997a0f56d6"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Graphs", "Trees"] | ["dfs and similar", "graphs", "trees", "*2700"] | https://codeforces.com/blog/entry/884 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9f75c8d4fa26670447f3b21157cc2656"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
43A | 43 | A | en | A. Football | <div class="problem-statement"><div class="header"><div class="title">A. Football</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="14aeb8a16830643ccd746450172298a1"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["strings", "*1000"] | https://codeforces.com/blog/entry/902 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8ee5473134c3d666d6230ec18c551d8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
43B | 43 | B | en | B. Letter | <div class="problem-statement"><div class="header"><div class="title">B. Letter</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="3032da62bf30aabd22619baf4b71a2c3"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["implementation", "strings", "*1100"] | https://codeforces.com/blog/entry/902 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8ee5473134c3d666d6230ec18c551d8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
43C | 43 | C | en | C. Lucky Tickets | <div class="problem-statement"><div class="header"><div class="title">C. Lucky Tickets</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="20420c3ee3e65dc98d93227127f18d7c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*1300"] | https://codeforces.com/blog/entry/902 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8ee5473134c3d666d6230ec18c551d8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
43D | 43 | D | en | D. Journey | <div class="problem-statement"><div class="header"><div class="title">D. Journey</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a658fc35e9ea079f006304d76637c548"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Constructive algorithms", "Implementation problems, programming technics, simulation"] | ["brute force", "constructive algorithms", "implementation", "*2000"] | https://codeforces.com/blog/entry/902 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8ee5473134c3d666d6230ec18c551d8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
43E | 43 | E | en | E. Race | <div class="problem-statement"><div class="header"><div class="title">E. Race</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="dc7b682db1cfa408896f12901e9bc673"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Implementation problems, programming technics, simulation", "Two pointers"] | ["brute force", "implementation", "two pointers", "*2300"] | https://codeforces.com/blog/entry/902 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8ee5473134c3d666d6230ec18c551d8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44A | 44 | A | en | A. Indian Summer | <div class="problem-statement"><div class="header"><div class="title">A. Indian Summer</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1a4518aae76d60021f3d5eebd54da8de"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*900"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44B | 44 | B | en | B. Cola | <div class="problem-statement"><div class="header"><div class="title">B. Cola</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="18010949043370c8f251206c9a9dbe7f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1500"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44C | 44 | C | en | C. Holidays | <div class="problem-statement"><div class="header"><div class="title">C. Holidays</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="38c4208caeb59bdc908bb8e91ec36163"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44D | 44 | D | en | D. Hyperdrive | <div class="problem-statement"><div class="header"><div class="title">D. Hyperdrive</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="aa1cd751f9ace9c1f2e3985e52c814cc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*1800"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44E | 44 | E | en | E. Anfisa the Monkey | <div class="problem-statement"><div class="header"><div class="title">E. Anfisa the Monkey</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cla... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="de997383a1504353a4a4290642963344"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*1400"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44F | 44 | F | en | F. BerPaint | <div class="problem-statement"><div class="header"><div class="title">F. BerPaint</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2616d12229006895bb5f86b44c6eada"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Graphs"] | ["geometry", "graphs", "*2700"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44G | 44 | G | en | G. Shooting Gallery | <div class="problem-statement"><div class="header"><div class="title">G. Shooting Gallery</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="024540895e3bc638ec3e922e656c0b76"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Implementation problems, programming technics, simulation"] | ["data structures", "implementation", "*2500"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44H | 44 | H | en | H. Phone Number | <div class="problem-statement"><div class="header"><div class="title">H. Phone Number</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bcc8c6292f7a98ebf08412c0e82ff9ac"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*1700"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44I | 44 | I | en | I. Toys | <div class="problem-statement"><div class="header"><div class="title">I. Toys</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="03bcbb9e066d9ea83c6d4275b1e4763c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Combinatorics"] | ["brute force", "combinatorics", "*2300"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
44J | 44 | J | en | J. Triminoes | <div class="problem-statement"><div class="header"><div class="title">J. Triminoes</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b92aed31010b7fe51eec5f1bbd5e15d5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Greedy algorithms"] | ["constructive algorithms", "greedy", "*2000"] | https://codeforces.com/blog/entry/833 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="422eb5e42f1a93f7d3660624dba5546f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
45A | 45 | A | en | A. Codecraft III | <div class="problem-statement"><div class="header"><div class="title">A. Codecraft III</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="13bec473c382749cddd411f601c0ad31"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*900"] | ||
45B | 45 | B | en | B. School | <div class="problem-statement"><div class="header"><div class="title">B. School</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="bbf14d125c9ab0f0e7f1e6f40ec2a5b9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Disjoint set union"] | ["dp", "dsu", "*2200"] | ||
45C | 45 | C | en | C. Dancing Lessons | <div class="problem-statement"><div class="header"><div class="title">C. Dancing Lessons</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="947a38f7ce69f89707cf32e5e3f674e4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc"] | ["data structures", "*1900"] | ||
45D | 45 | D | en | D. Event Dates | <div class="problem-statement"><div class="header"><div class="title">D. Event Dates</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="dc3699fd643405b138f61e5f25924dcd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Meet-in-the-middle", "Sortings, orderings"] | ["greedy", "meet-in-the-middle", "sortings", "*1900"] | ||
45E | 45 | E | en | E. Director | <div class="problem-statement"><div class="header"><div class="title">E. Director</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1ac639cc800b4b6f842d2deb7969672c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Greedy algorithms"] | ["constructive algorithms", "greedy", "*2000"] | ||
45F | 45 | F | en | F. Goats and Wolves | <div class="problem-statement"><div class="header"><div class="title">F. Goats and Wolves</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="18f9a9162e1ed0a35ea904bcb89984d8"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*2500"] | ||
45G | 45 | G | en | G. Prime Problem | <div class="problem-statement"><div class="header"><div class="title">G. Prime Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1a8c0821782ddb4a6a4fc314886e58ba"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Number theory: Euler function, GCD, divisibility, etc"] | ["number theory", "*2200"] | ||
45H | 45 | H | en | H. Road Problem | <div class="problem-statement"><div class="header"><div class="title">H. Road Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="25f26b879f82c3841d8ed50588c1fd7b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Graphs"] | ["graphs", "*2100"] | ||
45I | 45 | I | en | I. TCMCF+++ | <div class="problem-statement"><div class="header"><div class="title">I. TCMCF+++</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="3f762adf72f3d4c8e70664d45afb49dd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*1400"] | ||
45J | 45 | J | en | J. Planting Trees | <div class="problem-statement"><div class="header"><div class="title">J. Planting Trees</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b26d80b54d28e860f54605b928d8d898"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms"] | ["constructive algorithms", "*1800"] | ||
46A | 46 | A | en | A. Ball Game | <div class="problem-statement"><div class="header"><div class="title">A. Ball Game</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8acc9fa28f8a8da9a90a62f65a6560d6"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Implementation problems, programming technics, simulation"] | ["brute force", "implementation", "*800"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
46B | 46 | B | en | B. T-shirts from Sponsor | <div class="problem-statement"><div class="header"><div class="title">B. T-shirts from Sponsor</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="03c840c0edfc67dfaf129136ec07392d"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1100"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
46C | 46 | C | en | C. Hamsters and Tigers | <div class="problem-statement"><div class="header"><div class="title">C. Hamsters and Tigers</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div c... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a00afb3dd1871966fb70f2b2c749a9f5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Two pointers"] | ["two pointers", "*1600"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
46D | 46 | D | en | D. Parking Lot | <div class="problem-statement"><div class="header"><div class="title">D. Parking Lot</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1dc8faa9aa433c242f58d30271f2dba7"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Implementation problems, programming technics, simulation"] | ["data structures", "implementation", "*1800"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
46E | 46 | E | en | E. Comb | <div class="problem-statement"><div class="header"><div class="title">E. Comb</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-t... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5ceaa2b7077f54def8578e759ae4f5d1"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Dynamic programming"] | ["data structures", "dp", "*1900"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
46F | 46 | F | en | F. Hercule Poirot Problem | <div class="problem-statement"><div class="header"><div class="title">F. Hercule Poirot Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><di... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="dcc8ccb731f45bd888de243d82d8fc8e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Disjoint set union", "Graphs"] | ["dsu", "graphs", "*2300"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
46G | 46 | G | en | G. Emperor's Problem | <div class="problem-statement"><div class="header"><div class="title">G. Emperor's Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cla... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="241d639363bdaaadd09c79794b931100"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry"] | ["geometry", "*2500"] | https://codeforces.com/blog/entry/916 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b47e03912195120523561506745c8213"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
47A | 47 | A | en | A. Triangular numbers | <div class="problem-statement"><div class="header"><div class="title">A. Triangular numbers</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b39ef6113dc4146cdbf9982cf58c5105"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Mathematics including integration, differential equations, etc"] | ["brute force", "math", "*800"] | https://codeforces.com/blog/entry/931 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="87a8980d1d802b6c511fd12795b2407c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
47B | 47 | B | en | B. Coins | <div class="problem-statement"><div class="header"><div class="title">B. Coins</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="30910731566333ac9253e25c3ed0ddbe"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1200"] | https://codeforces.com/blog/entry/931 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="87a8980d1d802b6c511fd12795b2407c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
47C | 47 | C | en | C. Crossword | <div class="problem-statement"><div class="header"><div class="title">C. Crossword</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f28c8df1b311f913887e372507643d12"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*2000"] | https://codeforces.com/blog/entry/931 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="87a8980d1d802b6c511fd12795b2407c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
47D | 47 | D | en | D. Safe | <div class="problem-statement"><div class="header"><div class="title">D. Safe</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
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<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*2200"] | https://codeforces.com/blog/entry/931 |
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47E | 47 | E | en | E. Cannon | <div class="problem-statement"><div class="header"><div class="title">E. Cannon</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ec767fa977dfa9ab605ae79ee49d47fe"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Geometry, computational geometry", "Sortings, orderings"] | ["data structures", "geometry", "sortings", "*2200"] | https://codeforces.com/blog/entry/931 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="87a8980d1d802b6c511fd12795b2407c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
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48A | 48 | A | en | A. Rock-paper-scissors | <div class="problem-statement"><div class="header"><div class="title">A. Rock-paper-scissors</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div c... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="dab7282d95c90b74fafaec34585d8d24"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation", "Scheduling Algorithms"] | ["implementation", "schedules", "*900"] | ||
48B | 48 | B | en | B. Land Lot | <div class="problem-statement"><div class="header"><div class="title">B. Land Lot</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="d6528640a8ed2042e3ae7328c2717183"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Implementation problems, programming technics, simulation"] | ["brute force", "implementation", "*1200"] | ||
48C | 48 | C | en | C. The Race | <div class="problem-statement"><div class="header"><div class="title">C. The Race</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="60b355c7f7bf50d21788ffef027d41a6"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*1800"] | ||
48D | 48 | D | en | D. Permutations | <div class="problem-statement"><div class="header"><div class="title">D. Permutations</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a46d7d8e3fa61e1db5c9f7f7c355198d"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms"] | ["greedy", "*1500"] | ||
48E | 48 | E | en | E. Ivan the Fool VS Gorynych the Dragon | <div class="problem-statement"><div class="header"><div class="title">E. Ivan the Fool VS Gorynych the Dragon</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="i... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="96172c8dd78e5e155bf718b7a934294a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Games, Sprague\u2013Grundy theorem", "Graphs"] | ["dp", "games", "graphs", "*2100"] | ||
48F | 48 | F | en | F. Snow sellers | <div class="problem-statement"><div class="header"><div class="title">F. Snow sellers</div><div class="time-limit"><div class="property-title">time limit per test</div>10 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="290b19af531a842cfe0da04ca2b7c75f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Sortings, orderings"] | ["greedy", "sortings", "*2800"] | ||
48G | 48 | G | en | G. Galaxy Union | <div class="problem-statement"><div class="header"><div class="title">G. Galaxy Union</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="e6109e7056145b6ab9067626751bb008"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Trees", "Two pointers"] | ["dp", "trees", "two pointers", "*2700"] | ||
48H | 48 | H | en | H. Black and White | <div class="problem-statement"><div class="header"><div class="title">H. Black and White</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="00562f18710e301741706147fcb7b092"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms"] | ["constructive algorithms", "*2800"] | ||
49A | 49 | A | en | A. Sleuth | <div class="problem-statement"><div class="header"><div class="title">A. Sleuth</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7fbd3acb611c8ccae14c35108a68d271"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*800"] | ||
49B | 49 | B | en | B. Sum | <div class="problem-statement"><div class="header"><div class="title">B. Sum</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-t... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7916fce0425242ab9f5299a5f69c1faf"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*1500"] | ||
49C | 49 | C | en | C. Disposition | <div class="problem-statement"><div class="header"><div class="title">C. Disposition</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f0cc02975d3f077f2d61d54c13237090"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms", "Mathematics including integration, differential equations, etc"] | ["constructive algorithms", "math", "*1700"] | ||
49D | 49 | D | en | D. Game | <div class="problem-statement"><div class="header"><div class="title">D. Game</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="63b7cd0d905031ae7ecdd5239a5c1c20"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Dynamic programming", "Implementation problems, programming technics, simulation"] | ["brute force", "dp", "implementation", "*1800"] | ||
49E | 49 | E | en | E. Common ancestor | <div class="problem-statement"><div class="header"><div class="title">E. Common ancestor</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="58274b89db66e95545dfd4d750542e77"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*2300"] | ||
50A | 50 | A | en | A. Domino piling | <div class="problem-statement"><div class="header"><div class="title">A. Domino piling</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5babd5dd91dcf6b15bce5d0e46fe2ede"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Mathematics including integration, differential equations, etc"] | ["greedy", "math", "*800"] | https://codeforces.com/blog/entry/1006 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1dc0c02462b89483827ea4377e5794e5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
50B | 50 | B | en | B. Choosing Symbol Pairs | <div class="problem-statement"><div class="header"><div class="title">B. Choosing Symbol Pairs</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="da245500d1b21db86ddda28e7225e9ed"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["strings", "*1500"] | https://codeforces.com/blog/entry/1006 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1dc0c02462b89483827ea4377e5794e5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
50C | 50 | C | en | C. Happy Farm 5 | <div class="problem-statement"><div class="header"><div class="title">C. Happy Farm 5</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b4f18c718cfad2d18dae02240bec036f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry"] | ["geometry", "*2000"] | https://codeforces.com/blog/entry/1006 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1dc0c02462b89483827ea4377e5794e5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
50D | 50 | D | en | D. Bombing | <div class="problem-statement"><div class="header"><div class="title">D. Bombing</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="proper... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b8ef89a4520f77022324835c12c91512"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search", "Dynamic programming", "Probabilities, expected values, statistics, random variables, etc"] | ["binary search", "dp", "probabilities", "*2100"] | https://codeforces.com/blog/entry/1006 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1dc0c02462b89483827ea4377e5794e5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
50E | 50 | E | en | E. Square Equation Roots | <div class="problem-statement"><div class="header"><div class="title">E. Square Equation Roots</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="75bbc76b49e58f332d023d25edc39a39"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc"] | ["math", "*2300"] | https://codeforces.com/blog/entry/1006 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1dc0c02462b89483827ea4377e5794e5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
51A | 51 | A | en | A. Cheaterius's Problem | <div class="problem-statement"><div class="header"><div class="title">A. Cheaterius's Problem</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div ... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="98d7a369e7397dc1c1b4b61961cb0097"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | ||
51B | 51 | B | en | B. bHTML Tables Analisys | <div class="problem-statement"><div class="header"><div class="title">B. bHTML Tables Analisys</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b7c6526df25cd0108b5ea2aa6cf49671"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Parsing expression grammar"] | ["expression parsing", "*1700"] | ||
51C | 51 | C | en | C. Three Base Stations | <div class="problem-statement"><div class="header"><div class="title">C. Three Base Stations</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9bf37e345edf12b34d18b9dc0e7c88f0"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search", "Greedy algorithms"] | ["binary search", "greedy", "*1800"] | ||
51D | 51 | D | en | D. Geometrical problem | <div class="problem-statement"><div class="header"><div class="title">D. Geometrical problem</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1fb899141b168cb311813e36ff977e46"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*2200"] | ||
51E | 51 | E | en | E. Pentagon | <div class="problem-statement"><div class="header"><div class="title">E. Pentagon</div><div class="time-limit"><div class="property-title">time limit per test</div>10 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8835328c7a6ed8a53028dc4bb0b59727"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics", "Graphs", "Matrix multiplication, determinant, Cramer's rule, systems of linear equations"] | ["combinatorics", "graphs", "matrices", "*2400"] | ||
51F | 51 | F | en | F. Caterpillar | <div class="problem-statement"><div class="header"><div class="title">F. Caterpillar</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9de716747d7d8748052a2e810aa0ed56"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Dynamic programming", "Graphs", "Trees"] | ["dfs and similar", "dp", "graphs", "trees", "*2800"] | ||
52A | 52 | A | en | A. 123-sequence | <div class="problem-statement"><div class="header"><div class="title">A. 123-sequence</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7472d04b392f4f1f2cee0abbf60dcffd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*900"] | ||
52B | 52 | B | en | B. Right Triangles | <div class="problem-statement"><div class="header"><div class="title">B. Right Triangles</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="369b9a4bed1c5ee89749359240fbc6d9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics"] | ["combinatorics", "*1600"] | ||
52C | 52 | C | en | C. Circular RMQ | <div class="problem-statement"><div class="header"><div class="title">C. Circular RMQ</div><div class="time-limit"><div class="property-title">time limit per test</div>1.5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="68a3b7c842084d88c6fbf330eea5a30c"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc"] | ["data structures", "*2200"] | ||
53A | 53 | A | en | A. Autocomplete | <div class="problem-statement"><div class="header"><div class="title">A. Autocomplete</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="p... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="987f3765c44de1376531efef35d8c4ae"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1100"] | https://codeforces.com/blog/entry/1065 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b06bfd3490e7ae9dd4bfb22ef9be6e8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
53B | 53 | B | en | B. Blog Photo | <div class="problem-statement"><div class="header"><div class="title">B. Blog Photo</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="a2b8387fbadcea606fe6ee73d260659e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search", "Implementation problems, programming technics, simulation"] | ["binary search", "implementation", "*1700"] | https://codeforces.com/blog/entry/1065 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b06bfd3490e7ae9dd4bfb22ef9be6e8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
53C | 53 | C | en | C. Little Frog | <div class="problem-statement"><div class="header"><div class="title">C. Little Frog</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pr... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f2f4cb647f0cf380fa7a9a6fc5a8703b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Constructive algorithms"] | ["constructive algorithms", "*1200"] | https://codeforces.com/blog/entry/1065 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b06bfd3490e7ae9dd4bfb22ef9be6e8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
53D | 53 | D | en | D. Physical Education | <div class="problem-statement"><div class="header"><div class="title">D. Physical Education</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="8ab932b51e2669d9455c5d3755e99d0d"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Sortings, orderings"] | ["sortings", "*1500"] | https://codeforces.com/blog/entry/1065 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b06bfd3490e7ae9dd4bfb22ef9be6e8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
53E | 53 | E | en | E. Dead Ends | <div class="problem-statement"><div class="header"><div class="title">E. Dead Ends</div><div class="time-limit"><div class="property-title">time limit per test</div>5 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prop... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="7adeef3e40fbb971f9700a53d26e0ff9"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Bitmasks", "Dynamic programming"] | ["bitmasks", "dp", "*2500"] | https://codeforces.com/blog/entry/1065 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b06bfd3490e7ae9dd4bfb22ef9be6e8f"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
54A | 54 | A | en | A. Presents | <div class="problem-statement"><div class="header"><div class="title">A. Presents</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="e6532e23d981121fdb439c463e11649a"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | https://codeforces.com/blog/entry/1085 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9473e10add7088b4f8e4b8826329f140"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
54B | 54 | B | en | B. Cutting Jigsaw Puzzle | <div class="problem-statement"><div class="header"><div class="title">B. Cutting Jigsaw Puzzle</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5db9dc2a8b2a033dd76f37e034cdbb80"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Hashing, hashtables", "Implementation problems, programming technics, simulation"] | ["hashing", "implementation", "*1800"] | https://codeforces.com/blog/entry/1085 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9473e10add7088b4f8e4b8826329f140"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
54C | 54 | C | en | C. First Digit Law | <div class="problem-statement"><div class="header"><div class="title">C. First Digit Law</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="31a268e3fcff676b39e54d2c3c5655ad"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Mathematics including integration, differential equations, etc", "Probabilities, expected values, statistics, random variables, etc"] | ["dp", "math", "probabilities", "*2000"] | https://codeforces.com/blog/entry/1085 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9473e10add7088b4f8e4b8826329f140"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
54D | 54 | D | en | D. Writing a Song | <div class="problem-statement"><div class="header"><div class="title">D. Writing a Song</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class=... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5a9dda9d1e65394753fab3986e15dccd"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force", "Dynamic programming", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["brute force", "dp", "strings", "*2100"] | https://codeforces.com/blog/entry/1085 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9473e10add7088b4f8e4b8826329f140"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
54E | 54 | E | en | E. Vacuum Сleaner | <div class="problem-statement"><div class="header"><div class="title">E. Vacuum Сleaner</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b8e8a00bb82a9e6ff6d95593fad29a48"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry"] | ["geometry", "*2700"] | https://codeforces.com/blog/entry/1085 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="9473e10add7088b4f8e4b8826329f140"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
55A | 55 | A | en | A. Flea travel | <div class="problem-statement"><div class="header"><div class="title">A. Flea travel</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="d3bc5cf8f0ef16034f7e7b357836180b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation", "Mathematics including integration, differential equations, etc"] | ["implementation", "math", "*1200"] | ||
55B | 55 | B | en | B. Smallest number | <div class="problem-statement"><div class="header"><div class="title">B. Smallest number</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="21bc3e1a7a1e8d5bda74fb2d94788388"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Brute force"] | ["brute force", "*1600"] | ||
55C | 55 | C | en | C. Pie or die | <div class="problem-statement"><div class="header"><div class="title">C. Pie or die</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="pro... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="63dd214b3e5bea5ef119b79caa0ceea1"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Games, Sprague\u2013Grundy theorem"] | ["games", "*1900"] | ||
55D | 55 | D | en | D. Beautiful numbers | <div class="problem-statement"><div class="header"><div class="title">D. Beautiful numbers</div><div class="time-limit"><div class="property-title">time limit per test</div>4 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cla... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="223fd7eb07d484e2c9d7aaaedeb5f12b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Number theory: Euler function, GCD, divisibility, etc"] | ["dp", "number theory", "*2500"] | ||
55E | 55 | E | en | E. Very simple problem | <div class="problem-statement"><div class="header"><div class="title">E. Very simple problem</div><div class="time-limit"><div class="property-title">time limit per test</div>3 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div c... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="84ae5fde147a5d73a8d2a92d8740b3c1"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Geometry, computational geometry", "Two pointers"] | ["geometry", "two pointers", "*2500"] | ||
56A | 56 | A | en | A. Bar | <div class="problem-statement"><div class="header"><div class="title">A. Bar</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property-t... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f4a3b965c5dfabdcdf5ff049079a185e"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1000"] | https://codeforces.com/blog/entry/1147 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1ad8da0aaf90aa865343cab51d7160ca"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
56B | 56 | B | en | B. Spoilt Permutation | <div class="problem-statement"><div class="header"><div class="title">B. Spoilt Permutation</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cl... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="36dec37a61439931d6547b541c094754"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1300"] | https://codeforces.com/blog/entry/1147 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1ad8da0aaf90aa865343cab51d7160ca"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
56C | 56 | C | en | C. Corporation Mail | <div class="problem-statement"><div class="header"><div class="title">C. Corporation Mail</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="cacce5beb0c3426d0e770d158538e0c5"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Heaps, binary search trees, segment trees, hash tables, etc", "Parsing expression grammar", "Implementation problems, programming technics, simulation"] | ["data structures", "expression parsing", "implementation", "*1700"] | https://codeforces.com/blog/entry/1147 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1ad8da0aaf90aa865343cab51d7160ca"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
56D | 56 | D | en | D. Changing a String | <div class="problem-statement"><div class="header"><div class="title">D. Changing a String</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div cla... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="f8dd8198e367a5185a477c2fb459ceb1"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming"] | ["dp", "*2100"] | https://codeforces.com/blog/entry/1147 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1ad8da0aaf90aa865343cab51d7160ca"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
56E | 56 | E | en | E. Domino Principle | <div class="problem-statement"><div class="header"><div class="title">E. Domino Principle</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div clas... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="232a351997898fd846b7234e918e5622"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Binary search", "Heaps, binary search trees, segment trees, hash tables, etc", "Sortings, orderings"] | ["binary search", "data structures", "sortings", "*2200"] | https://codeforces.com/blog/entry/1147 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1ad8da0aaf90aa865343cab51d7160ca"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
57A | 57 | A | en | A. Square Earth? | <div class="problem-statement"><div class="header"><div class="title">A. Square Earth?</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="b067e5293158b4f4c701baed933552ce"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dfs and similar", "Greedy algorithms", "Implementation problems, programming technics, simulation"] | ["dfs and similar", "greedy", "implementation", "*1300"] | https://codeforces.com/blog/entry/1171 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ce6ca9373d76d422a834978ac82e9761"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
57B | 57 | B | en | B. Martian Architecture | <div class="problem-statement"><div class="header"><div class="title">B. Martian Architecture</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div ... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="e39a59eabe3a8d23fb9e56b8aedeb57b"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Implementation problems, programming technics, simulation"] | ["implementation", "*1600"] | https://codeforces.com/blog/entry/1171 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ce6ca9373d76d422a834978ac82e9761"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
57C | 57 | C | en | C. Array | <div class="problem-statement"><div class="header"><div class="title">C. Array</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="5884cc000e9c3cc2ede8824ac6d979af"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Combinatorics", "Mathematics including integration, differential equations, etc"] | ["combinatorics", "math", "*1900"] | https://codeforces.com/blog/entry/1171 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ce6ca9373d76d422a834978ac82e9761"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
57D | 57 | D | en | D. Journey | <div class="problem-statement"><div class="header"><div class="title">D. Journey</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="propert... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="0032277b035ec5a61c9d20a868abc505"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Dynamic programming", "Mathematics including integration, differential equations, etc"] | ["dp", "math", "*2500"] | https://codeforces.com/blog/entry/1171 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ce6ca9373d76d422a834978ac82e9761"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
57E | 57 | E | en | E. Chess | <div class="problem-statement"><div class="header"><div class="title">E. Chess</div><div class="time-limit"><div class="property-title">time limit per test</div>2 seconds</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="property... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="1b8b05ddef00f7b0b04319d867172af4"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Mathematics including integration, differential equations, etc", "Shortest paths on weighted and unweighted graphs"] | ["math", "shortest paths", "*3000"] | https://codeforces.com/blog/entry/1171 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="ce6ca9373d76d422a834978ac82e9761"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
58A | 58 | A | en | A. Chat room | <div class="problem-statement"><div class="header"><div class="title">A. Chat room</div><div class="time-limit"><div class="property-title">time limit per test</div>1 second</div><div class="memory-limit"><div class="property-title">memory limit per test</div>256 megabytes</div><div class="input-file"><div class="prope... |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="c41dcfdcc6b99ad89691851b4bb3e8fc"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... | ["Greedy algorithms", "Prefix- and Z-functions, suffix structures, Knuth\u2013Morris\u2013Pratt algorithm, etc"] | ["greedy", "strings", "*1000"] | https://codeforces.com/blog/entry/1771 |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="X-Csrf-Token" content="37b1edf29e42b9090754c866e4781651"/>
<meta id="viewport" name="viewport" content="width=device-width, initial-scale=0.01"/>
... |
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