Split (3)

train · 7.26k rows

Problem ID stringlengths 2 6	Problem Description stringlengths 0 7.52k	Rating float64 800 3.5k	math bool 2 classes	greedy bool 2 classes	implementation bool 2 classes	dp bool 2 classes	data structures bool 2 classes	constructive algorithms bool 2 classes	brute force bool 2 classes	binary search bool 2 classes	sortings bool 2 classes	graphs bool 2 classes	__index_level_0__ int64 3 9.98k
475C	Problem - 475C - Codeforces =============== xa0 ]( "Bayan Contest Warm Up round + 50 tshirts!") . Then the brush is moved several times. Each time the brush is moved one unit right or down. The brush has been strictly inside the frame during the painting. The brush alters every cell it has covered at s...	2,100	false	true	false	false	false	true	true	false	false	false	7,932
386B	Everyone loves a freebie. Especially students. It is well-known that if in the night before exam a student opens window, opens the student's record-book and shouts loudly three times "Fly, freebie, fly!" — then flown freebie helps him to pass the upcoming exam. In the night before the exam on mathematical analysis _n_ ...	1,400	false	false	true	false	false	false	true	true	false	false	8,285
1372E	Omkar is building a house. He wants to decide how to make the floor plan for the last floor. Omkar's floor starts out as $$$n$$$ rows of $$$m$$$ zeros ($$$1 le n,m le 100$$$). Every row is divided into intervals such that every $$$0$$$ in the row is in exactly $$$1$$$ interval. For every interval for every row, Omkar c...	2,900	false	true	false	true	false	false	false	false	false	false	3,803
1817C	A polynomial $$$A(x)$$$ of degree $$$d$$$ is an expression of the form $$$A(x) = a_0 + a_1 x + a_2 x^2 + dots + a_d x^d$$$, where $$$a_i$$$ are integers, and $$$a_d eq 0$$$. Two polynomials $$$A(x)$$$ and $$$B(x)$$$ are called similar if there is an integer $$$s$$$ such that for any integer $$$x$$$ it holds that $$$$$...	2,400	true	false	false	false	false	false	false	false	false	false	1,371
665A	Buses run between the cities _A_ and _B_, the first one is at 05:00 AM and the last one departs not later than at 11:59 PM. A bus from the city _A_ departs every _a_ minutes and arrives to the city _B_ in a _t__a_ minutes, and a bus from the city _B_ departs every _b_ minutes and arrives to the city _A_ in a _t__b_ min...	1,600	false	false	true	false	false	false	false	false	false	false	7,161
1721B	The robot is placed in the top left corner of a grid, consisting of $$$n$$$ rows and $$$m$$$ columns, in a cell $$$(1, 1)$$$. In one step, it can move into a cell, adjacent by a side to the current one: $$$(x, y) ightarrow (x, y + 1)$$$; $$$(x, y) ightarrow (x + 1, y)$$$; $$$(x, y) ightarrow (x, y - 1)$$$; $$$(x...	1,000	false	false	true	false	false	false	false	false	false	false	1,958
1004D	Since Sonya has just learned the basics of matrices, she decided to play with them a little bit. Sonya imagined a new type of matrices that she called rhombic matrices. These matrices have exactly one zero, while all other cells have the Manhattan distance to the cell containing the zero. The cells with equal numbers h...	2,300	false	false	true	false	false	true	true	false	false	false	5,665
1337A	Ichihime is the current priestess of the Mahjong Soul Temple. She claims to be human, despite her cat ears. These days the temple is holding a math contest. Usually, Ichihime lacks interest in these things, but this time the prize for the winner is her favorite — cookies. Ichihime decides to attend the contest. Now she...	800	true	false	false	false	false	true	false	false	false	false	4,016
1430D	You have a string $$$s$$$ consisting of $$$n$$$ characters. Each character is either 0 or 1. You can perform operations on the string. Each operation consists of two steps: 1. select an integer $$$i$$$ from $$$1$$$ to the length of the string $$$s$$$, then delete the character $$$s_i$$$ (the string length gets reduced ...	1,700	false	true	false	false	true	false	false	true	false	false	3,513
1780F	One day Kira found $$$n$$$ friends from Morioh and decided to gather them around a table to have a peaceful conversation. The height of friend $$$i$$$ is equal to $$$a_i$$$. It so happened that the height of each of the friends is unique. Unfortunately, there were only $$$3$$$ chairs in Kira's house, and obviously, it ...	2,300	false	false	false	true	true	false	true	false	true	false	1,590
269A	Emuskald is a well-known illusionist. One of his trademark tricks involves a set of magical boxes. The essence of the trick is in packing the boxes inside other boxes. From the top view each magical box looks like a square with side length equal to 2_k_ (_k_ is an integer, _k_u2009≥u20090) units. A magical box _v_ can ...	1,600	true	true	false	false	false	false	false	false	false	false	8,758
1696E	We say an infinite sequence $$$a_{0}, a_{1}, a_2, ldots$$$ is non-increasing if and only if for all $$$ige 0$$$, $$$a_i ge a_{i+1}$$$. There is an infinite right and down grid. The upper-left cell has coordinates $$$(0,0)$$$. Rows are numbered $$$0$$$ to infinity from top to bottom, columns are numbered from $$$0$$$ to...	2,000	true	false	false	false	false	false	false	false	false	false	2,104
1928A	Bob has a rectangle of size $$$a imes b$$$. He tries to cut this rectangle into two rectangles with integer sides by making a cut parallel to one of the sides of the original rectangle. Then Bob tries to form some other rectangle from the two resulting rectangles, and he can rotate and move these two rectangles as he ...	800	true	false	false	false	false	false	false	false	false	false	723
1341A	Nastya just made a huge mistake and dropped a whole package of rice on the floor. Mom will come soon. If she sees this, then Nastya will be punished. In total, Nastya dropped $$$n$$$ grains. Nastya read that each grain weighs some integer number of grams from $$$a - b$$$ to $$$a + b$$$, inclusive (numbers $$$a$$$ and $...	900	true	false	false	false	false	false	false	false	false	false	4,001
1189B	You are given $$$n$$$ numbers $$$a_1, a_2, ldots, a_n$$$. Is it possible to arrange them in a circle in such a way that every number is strictly less than the sum of its neighbors? For example, for the array $$$[1, 4, 5, 6, 7, 8]$$$, the arrangement on the left is valid, while arrangement on the right is not, as $$$5ge...	1,100	true	true	false	false	false	false	false	false	true	false	4,752
923D	Alice has a string consisting of characters 'A', 'B' and 'C'. Bob can use the following transitions on any substring of our string in any order any number of times: Note that a substring is one or more consecutive characters. For given queries, determine whether it is possible to obtain the target string from source. I...	2,500	false	false	true	false	false	true	false	false	false	false	6,020
914E	You are given a tree (a connected acyclic undirected graph) of _n_ vertices. Vertices are numbered from 1 to _n_ and each vertex is assigned a character from a to t. A path in the tree is said to be palindromic if at least one permutation of the labels in the path is a palindrome. For each vertex, output the number of ...	2,400	false	false	false	false	true	false	false	false	false	false	6,079
39F	Thumbelina has had an accident. She has found herself on a little island in the middle of a swamp and wants to get to the shore very much. One can get to the shore only by hills that are situated along a straight line that connects the little island with the shore. Let us assume that the hills are numbered from 1 to _n...	1,300	false	false	true	false	false	false	false	false	false	false	9,795
403D	The sequence of integer pairs (_a_1,u2009_b_1),u2009(_a_2,u2009_b_2),u2009...,u2009(_a__k_,u2009_b__k_) is beautiful, if the following statements are fulfilled: 1u2009≤u2009_a_1u2009≤u2009_b_1u2009<u2009_a_2u2009≤u2009_b_2u2009<u2009...u2009<u2009_a__k_u2009≤u2009_b__k_u2009≤u2009_n_, where _n_ is a given positive int...	2,300	false	false	false	true	false	false	false	false	false	false	8,212
845E	The capital of Berland looks like a rectangle of size _n_u2009×u2009_m_ of the square blocks of same size. Fire! It is known that _k_u2009+u20091 blocks got caught on fire (_k_u2009+u20091u2009≤u2009_n_·_m_). Those blocks are centers of ignition. Moreover positions of _k_ of these centers are known and one of these sta...	2,400	false	false	false	false	true	false	false	true	false	false	6,380
615C	A boy named Ayrat lives on planet AMI-1511. Each inhabitant of this planet has a talent. Specifically, Ayrat loves running, moreover, just running is not enough for him. He is dreaming of making running a real art. First, he wants to construct the running track with coating _t_. On planet AMI-1511 the coating of the tr...	2,000	false	true	false	true	false	false	false	false	false	false	7,378
1814B	A robot is placed in a cell $$$(0, 0)$$$ of an infinite grid. This robot has adjustable length legs. Initially, its legs have length $$$1$$$. Let the robot currently be in the cell $$$(x, y)$$$ and have legs of length $$$m$$$. In one move, it can perform one of the following three actions: jump into the cell $$$(x + m...	1,700	true	false	false	false	false	false	true	false	false	false	1,386
444E	DZY loves planting, and he enjoys solving tree problems. DZY has a weighted tree (connected undirected graph without cycles) containing _n_ nodes (they are numbered from 1 to _n_). He defines the function _g_(_x_,u2009_y_) (1u2009≤u2009_x_,u2009_y_u2009≤u2009_n_) as the longest edge in the shortest path between nodes _...	2,700	false	false	false	false	false	false	false	true	false	false	8,059
912A	During the winter holidays, the demand for Christmas balls is exceptionally high. Since it's already 2018, the advances in alchemy allow easy and efficient ball creation by utilizing magic crystals. Grisha needs to obtain some yellow, green and blue balls. It's known that to produce a yellow ball one needs two yellow c...	800	false	false	true	false	false	false	false	false	false	false	6,096
1758D	You are given an integer $$$n$$$. Find a sequence of $$$n$$$ distinct integers $$$a_1, a_2, dots, a_n$$$ such that $$$1 leq a_i leq 10^9$$$ for all $$$i$$$ and $$$$$$max(a_1, a_2, dots, a_n) - min(a_1, a_2, dots, a_n)= sqrt{a_1 + a_2 + dots + a_n}.$$$$$$ It can be proven that there exists a sequence of distinct integer...	1,800	true	false	false	false	false	true	true	true	false	false	1,765
946E	Problem - 946E - Codeforces =============== xa0 ]( --- Finished → Virtual participation Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - s...	2,200	false	true	true	false	false	false	false	false	false	false	5,928
1366A	Problem - 1366A - Codeforces =============== xa0 ]( --- Finished → Virtual participation Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - ...	1,100	true	true	false	false	false	false	false	true	false	false	3,850
1555C	Alice and Bob are playing a game on a matrix, consisting of $$$2$$$ rows and $$$m$$$ columns. The cell in the $$$i$$$-th row in the $$$j$$$-th column contains $$$a_{i, j}$$$ coins in it. Initially, both Alice and Bob are standing in a cell $$$(1, 1)$$$. They are going to perform a sequence of moves to reach a cell $$$(...	1,300	false	false	true	true	false	true	true	false	false	false	2,859
833A	Slastyona and her loyal dog Pushok are playing a meaningless game that is indeed very interesting. The game consists of multiple rounds. Its rules are very simple: in each round, a natural number _k_ is chosen. Then, the one who says (or barks) it faster than the other wins the round. After that, the winner's score is ...	1,700	true	false	false	false	false	false	false	false	false	false	6,434
1466G	Whoso in ignorance draws near to them and hears the Sirens' voice, he nevermore returns. Homer, Odyssey In the times of Jason and the Argonauts, it was well known that sirens use the sound of their songs to lure sailors into their demise. Yet only a few knew that every time sirens call a sailor by his name, his will we...	2,600	true	false	false	false	false	false	false	false	false	false	3,360
637C	During a New Year special offer the "Sudislavl Bars" offered _n_ promo codes. Each promo code consists of exactly six digits and gives right to one free cocktail at the bar "Mosquito Shelter". Of course, all the promocodes differ. As the "Mosquito Shelter" opens only at 9, and partying in Sudislavl usually begins at as...	1,400	false	false	true	false	false	true	true	false	false	false	7,263
1858D	The teachers of the Summer Informatics School decided to plant $$$n$$$ trees in a row, and it was decided to plant only oaks and firs. To do this, they made a plan, which can be represented as a binary string $$$s$$$ of length $$$n$$$. If $$$s_i = 0$$$, then the $$$i$$$-th tree in the row should be an oak, and if $$$s_...	2,200	false	true	false	true	true	false	true	false	false	false	1,134
1144D	You are given an array $$$a$$$ consisting of $$$n$$$ integers. You can perform the following operations arbitrary number of times (possibly, zero): 1. Choose a pair of indices $$$(i, j)$$$ such that $$$i-j=1$$$ (indices $$$i$$$ and $$$j$$$ are adjacent) and set $$$a_i := a_i + a_i - a_j$$$; 2. Choose a pair of indices ...	1,400	false	true	false	false	false	true	false	false	false	false	5,002
1446C	For a given sequence of distinct non-negative integers $$$(b_1, b_2, dots, b_k)$$$ we determine if it is good in the following way: Consider a graph on $$$k$$$ nodes, with numbers from $$$b_1$$$ to $$$b_k$$$ written on them. For every $$$i$$$ from $$$1$$$ to $$$k$$$: find such $$$j$$$ ($$$1 le j le k$$$, $$$j eq i$$$...	2,100	false	false	false	true	true	false	false	true	false	false	3,445
1750F	Everyone was happy coding, until suddenly a power shortage happened and the best competitive programming site went down. Fortunately, a system administrator bought some new equipment recently, including some UPSs. Thus there are some servers that are still online, but we need all of them to be working in order to keep ...	2,700	true	false	false	true	false	false	false	false	false	false	1,780
584E	Anton loves transforming one permutation into another one by swapping elements for money, and Ira doesn't like paying for stupid games. Help them obtain the required permutation by paying as little money as possible. More formally, we have two permutations, _p_ and _s_ of numbers from 1 to _n_. We can swap _p__i_ and _...	2,300	true	true	false	false	false	true	false	false	false	false	7,506
723F	You are given an undirected connected graph consisting of _n_ vertices and _m_ edges. There are no loops and no multiple edges in the graph. You are also given two distinct vertices _s_ and _t_, and two values _d__s_ and _d__t_. Your task is to build any spanning tree of the given graph (note that the graph is not weig...	2,300	false	true	true	false	false	false	false	false	false	true	6,915
381A	Sereja and Dima play a game. The rules of the game are very simple. The players have _n_ cards in a row. Each card contains a number, all numbers on the cards are distinct. The players take turns, Sereja moves first. During his turn a player can take one card: either the leftmost card in a row, or the rightmost one. Th...	800	false	true	true	false	false	false	false	false	false	false	8,305
1738B	Suppose $$$a_1, a_2, dots, a_n$$$ is a sorted integer sequence of length $$$n$$$ such that $$$a_1 leq a_2 leq dots leq a_n$$$. For every $$$1 leq i leq n$$$, the prefix sum $$$s_i$$$ of the first $$$i$$$ terms $$$a_1, a_2, dots, a_i$$$ is defined by $$$$$$ s_i = sum_{k=1}^i a_k = a_1 + a_2 + dots + a_i. $$$$$$ Now you ...	1,200	true	true	false	false	false	true	false	false	true	false	1,860
804D	Pasha is a good student and one of MoJaK's best friends. He always have a problem to think about. Today they had a talk about the following problem. We have a forest (acyclic undirected graph) with _n_ vertices and _m_ edges. There are _q_ queries we should answer. In each query two vertices _v_ and _u_ are given. Let ...	2,500	false	false	false	true	false	false	true	true	true	false	6,542
1032C	Little Paul wants to learn how to play piano. He already has a melody he wants to start with. For simplicity he represented this melody as a sequence $$$a_1, a_2, ldots, a_n$$$ of key numbers: the more a number is, the closer it is to the right end of the piano keyboard. Paul is very clever and knows that the essential...	1,700	false	false	false	true	false	true	false	false	false	false	5,540
68D	Recently Petya has become keen on physics. Anna V., his teacher noticed Petya's interest and gave him a fascinating physical puzzle — a half-decay tree. A half-decay tree is a complete binary tree with the height _h_. The height of a tree is the length of the path (in edges) from the root to a leaf in the tree. While s...	2,500	true	false	false	true	true	false	false	false	false	false	9,628
440C	. Output Print expected minimal number of digits 1.	1,800	false	false	false	false	false	false	true	false	false	false	8,077
1537E2	This is the hard version of the problem. The only difference is the constraints on $$$n$$$ and $$$k$$$. You can make hacks only if all versions of the problem are solved. You have a string $$$s$$$, and you can do two types of operations on it: Delete the last character of the string. Duplicate the string: $$$s:=s+s$$...	2,200	false	true	false	false	true	false	false	true	false	false	2,957
1896D	You are given a $$$1$$$-indexed array $$$a$$$ of length $$$n$$$ where each element is $$$1$$$ or $$$2$$$. Process $$$q$$$ queries of the following two types: "1 s": check if there exists a subarray$$$^{dagger}$$$ of $$$a$$$ whose sum equals to $$$s$$$. "2 i v": change $$$a_i$$$ to $$$v$$$. $$$^{dagger}$$$ An array $$...	1,700	true	false	false	false	true	false	false	true	false	false	934
305B	Problem - 305B - Codeforces =============== xa0 ]( --- Finished → Virtual participation 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. If you've seen these problems, a virtual contest is not for you - s...	1,700	true	false	true	false	false	false	true	false	false	false	8,615
1783C	You are participating in Yet Another Tournament. There are $$$n + 1$$$ participants: you and $$$n$$$ other opponents, numbered from $$$1$$$ to $$$n$$$. Each two participants will play against each other exactly once. If the opponent $$$i$$$ plays against the opponent $$$j$$$, he wins if and only if $$$i > j$$$. When th...	1,700	false	true	false	false	false	false	false	true	true	false	1,577
545B	Little Susie loves strings. Today she calculates distances between them. As Susie is a small girl after all, her strings contain only digits zero and one. She uses the definition of Hamming distance: We will define the distance between two strings _s_ and _t_ of the same length consisting of digits zero and one as the ...	1,100	false	true	false	false	false	false	false	false	false	false	7,661
342D	Xenia likes puzzles very much. She is especially fond of the puzzles that consist of domino pieces. Look at the picture that shows one of such puzzles. A puzzle is a 3u2009×u2009_n_ table with forbidden cells (black squares) containing dominoes (colored rectangles on the picture). A puzzle is called correct if it meets...	2,100	false	false	false	true	false	false	false	false	false	false	8,465
815B	Karen has just arrived at school, and she has a math test today! The test is about basic addition and subtraction. Unfortunately, the teachers were too busy writing tasks for Codeforces rounds, and had no time to make an actual test. So, they just put one question in the test that is worth all the points. There are _n_...	2,200	true	false	false	false	false	true	true	false	false	false	6,499
1028F	Consider a set of points $$$A$$$, initially it is empty. There are three types of queries: 1. Insert a point $$$(x_i, y_i)$$$ to $$$A$$$. It is guaranteed that this point does not belong to $$$A$$$ at this moment. 2. Remove a point $$$(x_i, y_i)$$$ from $$$A$$$. It is guaranteed that this point belongs to $$$A$$$ at th...	2,900	false	false	false	false	false	false	true	false	false	false	5,564
2005D	You are given two arrays $$$a_1, a_2, ldots, a_n$$$ and $$$b_1, b_2, ldots, b_n$$$. You must perform the following operation exactly once: choose any indices $$$l$$$ and $$$r$$$ such that $$$1 le l le r le n$$$; swap $$$a_i$$$ and $$$b_i$$$ for all $$$i$$$ such that $$$l leq i leq r$$$. Find the maximum possible valu...	2,400	false	false	true	false	true	false	true	true	false	false	220
1176F	You are playing a computer card game called Splay the Sire. Currently you are struggling to defeat the final boss of the game. The boss battle consists of $$$n$$$ turns. During each turn, you will get several cards. Each card has two parameters: its cost $$$c_i$$$ and damage $$$d_i$$$. You may play some of your cards d...	2,100	false	false	true	true	false	false	false	false	true	false	4,833
573A	Problem - 573A - Codeforces =============== xa0 ]( --- Finished → Virtual participation 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. If you've seen these problems, a virtual contest is not for you - s...	1,300	true	false	true	false	false	false	false	false	false	false	7,559
580C	Kefa decided to celebrate his first big salary by going to the restaurant. He lives by an unusual park. The park is a rooted tree consisting of _n_ vertices with the root at vertex 1. Vertex 1 also contains Kefa's house. Unfortunaely for our hero, the park also contains cats. Kefa has already found out what are the ver...	1,500	false	false	false	false	false	false	false	false	false	true	7,526
1957F2	This is the hard version of the problem. The difference between the two versions of this problem is the constraint on $$$k$$$. You can make hacks only if all versions of the problem are solved. You are given an undirected tree of $$$n$$$ nodes. Each node $$$v$$$ has a value $$$a_v$$$ written on it. You have to answer q...	2,700	false	false	false	false	true	false	false	true	false	false	527
447A	Problem - 447A - Codeforces =============== xa0 ]( --- Finished → Virtual participation 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. If you've seen these problems, a virtual contest is not for you - s...	800	false	false	true	false	false	false	false	false	false	false	8,051
1863D	There is an $$$n imes m$$$ board divided into cells. There are also some dominoes on this board. Each domino covers two adjacent cells (that is, two cells that share a side), and no two dominoes overlap. Piet thinks that this board is too boring and it needs to be painted. He will paint the cells of the dominoes black ...	1,400	false	true	false	false	false	true	false	false	false	false	1,103
1322F	Mayor of city M. decided to launch several new metro lines during 2020. Since the city has a very limited budget, it was decided not to dig new tunnels but to use the existing underground network. The tunnel system of the city M. consists of $$$n$$$ metro stations. The stations are connected with $$$n - 1$$$ bidirectio...	3,500	false	false	false	true	false	false	false	false	false	false	4,102
240E	A country named Berland has _n_ cities. They are numbered with integers from 1 to _n_. City with index 1 is the capital of the country. Some pairs of cities have monodirectional roads built between them. However, not all of them are in good condition. For each road we know whether it needs repairing or not. If a road n...	2,800	false	true	false	false	false	false	false	false	false	true	8,877
1044C	You are given $$$n$$$ points on the plane. The polygon formed from all the $$$n$$$ points is strictly convex, that is, the polygon is convex, and there are no three collinear points (i.e. lying in the same straight line). The points are numbered from $$$1$$$ to $$$n$$$, in clockwise order. We define the distance betwee...	2,100	false	false	false	true	false	false	false	false	false	false	5,474
229B	Goa'uld Apophis captured Jack O'Neill's team again! Jack himself was able to escape, but by that time Apophis's ship had already jumped to hyperspace. But Jack knows on what planet will Apophis land. In order to save his friends, Jack must repeatedly go through stargates to get to this planet. Overall the galaxy has _n...	1,700	false	false	false	false	true	false	false	true	false	true	8,922
1550A	Let's call an array $$$a$$$ consisting of $$$n$$$ positive (greater than $$$0$$$) integers beautiful if the following condition is held for every $$$i$$$ from $$$1$$$ to $$$n$$$: either $$$a_i = 1$$$, or at least one of the numbers $$$a_i - 1$$$ and $$$a_i - 2$$$ exists in the array as well. For example: the array $$$...	800	true	true	false	false	false	false	false	false	false	false	2,898
1609D	William arrived at a conference dedicated to cryptocurrencies. Networking, meeting new people, and using friends' connections are essential to stay up to date with the latest news from the world of cryptocurrencies. The conference has $$$n$$$ participants, who are initially unfamiliar with each other. William can intro...	1,600	false	true	true	false	false	false	false	false	false	true	2,605
492D	Vanya and his friend Vova play a computer game where they need to destroy _n_ monsters to pass a level. Vanya's character performs attack with frequency _x_ hits per second and Vova's character performs attack with frequency _y_ hits per second. Each character spends fixed time to raise a weapon and then he hits (the t...	1,800	true	false	true	false	false	false	false	true	true	false	7,865
1474F	Igor had a sequence $$$d_1, d_2, dots, d_n$$$ of integers. When Igor entered the classroom there was an integer $$$x$$$ written on the blackboard. Igor generated sequence $$$p$$$ using the following algorithm: 1. initially, $$$p = [x]$$$; 2. for each $$$1 leq i leq n$$$ he did the following operation $$$d_i$$$ times: ...	3,000	true	false	false	true	false	false	false	false	false	false	3,305
163B	As you know, lemmings like jumping. For the next spectacular group jump _n_ lemmings gathered near a high rock with _k_ comfortable ledges on it. The first ledge is situated at the height of _h_ meters, the second one is at the height of 2_h_ meters, and so on (the _i_-th ledge is at the height of _i_·_h_ meters). The ...	2,000	false	false	false	false	false	false	false	true	false	false	9,214
746E	Eugeny has _n_ cards, each of them has exactly one integer written on it. Eugeny wants to exchange some cards with Nikolay so that the number of even integers on his cards would equal the number of odd integers, and that all these numbers would be distinct. Nikolay has _m_ cards, distinct numbers from 1 to _m_ are writ...	1,900	true	true	true	false	false	false	false	false	false	false	6,813
1475E	Masha works in an advertising agency. In order to promote the new brand, she wants to conclude contracts with some bloggers. In total, Masha has connections of $$$n$$$ different bloggers. Blogger numbered $$$i$$$ has $$$a_i$$$ followers. Since Masha has a limited budget, she can only sign a contract with $$$k$$$ differ...	1,600	true	false	false	false	false	false	false	false	true	false	3,300
766E	Mahmoud and Ehab live in a country with _n_ cities numbered from 1 to _n_ and connected by _n_u2009-u20091 undirected roads. It's guaranteed that you can reach any city from any other using these roads. Each city has a number _a__i_ attached to it. We define the distance from city _x_ to city _y_ as the xor of numbers ...	2,100	true	false	false	true	true	true	false	false	false	false	6,719
1375F	This is an interactive problem. Anton and Harris are playing a game to decide which of them is the king of problemsetting. There are three piles of stones, initially containing $$$a$$$, $$$b$$$, and $$$c$$$ stones, where $$$a$$$, $$$b$$$, and $$$c$$$ are distinct positive integers. On each turn of the game, the followi...	2,600	true	false	false	false	false	true	false	false	false	false	3,782
838D	There is an airplane which has _n_ rows from front to back. There will be _m_ people boarding this airplane. This airplane has an entrance at the very front and very back of the plane. Each person has some assigned seat. It is possible for multiple people to have the same assigned seat. The people will then board the p...	2,700	true	false	false	false	false	false	false	false	false	false	6,411
1980D	GCD (Greatest Common Divisor) of two integers $$$x$$$ and $$$y$$$ is the maximum integer $$$z$$$ by which both $$$x$$$ and $$$y$$$ are divisible. For example, $$$GCD(36, 48) = 12$$$, $$$GCD(5, 10) = 5$$$, and $$$GCD(7,11) = 1$$$. Kristina has an array $$$a$$$ consisting of exactly $$$n$$$ positive integers. She wants t...	1,400	true	true	true	false	false	false	false	false	false	false	407
623E	Problem - 623E - Codeforces =============== xa0 ]( --- Finished → Virtual participation Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - s...	3,300	true	false	false	true	false	false	false	false	false	false	7,336
906E	Problem - 906E - Codeforces =============== xa0 ]( --- Finished → Virtual participation Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - s...	3,300	false	false	false	true	false	false	false	false	false	false	6,123
997C	Problem - 997C - Codeforces =============== xa0 ]( --- Finished → Virtual participation Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - s...	2,500	true	false	false	false	false	false	false	false	false	false	5,716
1555A	PizzaForces is Petya's favorite pizzeria. PizzaForces makes and sells pizzas of three sizes: small pizzas consist of $$$6$$$ slices, medium ones consist of $$$8$$$ slices, and large pizzas consist of $$$10$$$ slices each. Baking them takes $$$15$$$, $$$20$$$ and $$$25$$$ minutes, respectively. Petya's birthday is today...	900	true	false	false	false	false	false	true	false	false	false	2,861
1691C	You are given a binary string $$$s$$$ of length $$$n$$$. Let's define $$$d_i$$$ as the number whose decimal representation is $$$s_i s_{i+1}$$$ (possibly, with a leading zero). We define $$$f(s)$$$ to be the sum of all the valid $$$d_i$$$. In other words, $$$f(s) = sumlimits_{i=1}^{n-1} d_i$$$. For example, for the str...	1,400	true	true	false	false	false	true	true	false	false	false	2,134
939D	Valya and Tolya are an ideal pair, but they quarrel sometimes. Recently, Valya took offense at her boyfriend because he came to her in t-shirt with lettering that differs from lettering on her pullover. Now she doesn't want to see him and Tolya is seating at his room and crying at her photos all day long. This story co...	1,600	false	true	false	false	false	false	false	false	false	true	5,941
1581B	CQXYM wants to create a connected undirected graph with $$$n$$$ nodes and $$$m$$$ edges, and the diameter of the graph must be strictly less than $$$k-1$$$. Also, CQXYM doesn't want a graph that contains self-loops or multiple edges (i.e. each edge connects two different vertices and between each pair of vertices there...	1,200	true	true	false	false	false	true	false	false	false	true	2,726
266B	During the break the schoolchildren, boys and girls, formed a queue of _n_ people in the canteen. Initially the children stood in the order they entered the canteen. However, after a while the boys started feeling awkward for standing in front of the girls in the queue and they started letting the girls move forward ea...	800	false	false	true	false	false	true	false	false	false	false	8,770
2033A	Sakurako and Kosuke decided to play some games with a dot on a coordinate line. The dot is currently located in position $$$x=0$$$. They will be taking turns, and Sakurako will be the one to start. On the $$$i$$$-th move, the current player will move the dot in some direction by $$$2cdot i-1$$$ units. Sakurako will alw...	800	true	false	true	false	false	true	false	false	false	false	68
1684E	You are given an array $$$a$$$ of $$$n$$$ non-negative integers. In one operation you can change any number in the array to any other non-negative integer. Let's define the cost of the array as $$$operatorname{DIFF}(a) - operatorname{MEX}(a)$$$, where $$$operatorname{MEX}$$$ of a set of non-negative integers is the sma...	2,100	false	true	false	false	true	true	true	true	false	false	2,169
992E	Nastya likes reading and even spends whole days in a library sometimes. Today she found a chronicle of Byteland in the library, and it stated that there lived shamans long time ago. It is known that at every moment there was exactly one shaman in Byteland, and there were _n_ shamans in total enumerated with integers fr...	2,500	false	false	false	false	true	false	false	true	false	false	5,735
494A	Malek has recently found a treasure map. While he was looking for a treasure he found a locked door. There was a string _s_ written on the door consisting of characters '(', ')' and '#'. Below there was a manual on how to open the door. After spending a long time Malek managed to decode the manual and found out that th...	1,500	false	true	false	false	false	false	false	false	false	false	7,858
83C	You already know that Valery's favorite sport is biathlon. Due to your help, he learned to shoot without missing, and his skills are unmatched at the shooting range. But now a smaller task is to be performed, he should learn to complete the path fastest. The track's map is represented by a rectangle _n_u2009×u2009_m_ i...	2,400	false	true	false	false	false	false	false	false	false	true	9,551
115A	A company has _n_ employees numbered from 1 to _n_. Each employee either has no immediate manager or exactly one immediate manager, who is another employee with a different number. An employee _A_ is said to be the superior of another employee _B_ if at least one of the following is true: Employee _A_ is the immediate...	900	false	false	false	false	false	false	false	false	false	true	9,428
732A	Polycarp urgently needs a shovel! He comes to the shop and chooses an appropriate one. The shovel that Policarp chooses is sold for _k_ burles. Assume that there is an unlimited number of such shovels in the shop. In his pocket Polycarp has an unlimited number of "10-burle coins" and exactly one coin of _r_ burles (1u2...	800	true	false	true	false	false	true	true	false	false	false	6,870
1091G	Integer factorisation is hard. The RSA Factoring Challenge offered $$$$100,000$$$ for factoring RSA-$$$1024$$$, a $$$1024$$$-bit long product of two prime numbers. To this date, nobody was able to claim the prize. We want you to factorise a $$$1024$$$-bit number. Since your programming language of choice might not offe...	3,200	true	false	false	false	false	false	false	false	false	false	5,253
1088B	Problem - 1088B - Codeforces =============== xa0 ]( --- Finished → Virtual participation 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. If you've seen these problems, a virtual contest is not for you - ...	1,000	false	false	true	false	false	false	false	false	true	false	5,290
1893C	Let's define the anti-beauty of a multiset $$${b_1, b_2, ldots, b_{len}}$$$ as the number of occurrences of the number $$$len$$$ in the multiset. You are given $$$m$$$ multisets, where the $$$i$$$-th multiset contains $$$n_i$$$ distinct elements, specifically: $$$c_{i, 1}$$$ copies of the number $$$a_{i,1}$$$, $$$c_{i,...	2,000	false	true	true	false	false	false	true	false	false	false	949
125B	Let's define a string <x> as an opening tag, where _x_ is any small letter of the Latin alphabet. Each opening tag matches a closing tag of the type </x>, where _x_ is the same letter. Tegs can be nested into each other: in this case one opening and closing tag pair is located inside another pair. Let's define the noti...	1,000	false	false	true	false	false	false	false	false	false	false	9,381
290C	Problem - 290C - Codeforces =============== xa0 . Output Output a single real number. The answer is considered to be correct if its absolute or relative error does not exceed 10u2009-u20094. Examples Input 3 0 1 1 Output 0.666667	1,700	false	false	true	false	false	false	false	false	false	false	8,675
593D	Bogdan has a birthday today and mom gave him a tree consisting of _n_ vertecies. For every edge of the tree _i_, some number _x__i_ was written on it. In case you forget, a tree is a connected non-directed graph without cycles. After the present was granted, _m_ guests consecutively come to Bogdan's party. When the _i_...	2,400	true	false	false	false	true	false	false	false	false	true	7,474
295C	One day Greg and his friends were walking in the forest. Overall there were _n_ people walking, including Greg. Soon he found himself in front of a river. The guys immediately decided to get across the river. Luckily, there was a boat by the river bank, just where the guys were standing. We know that the boat can hold ...	2,100	false	false	false	true	false	false	false	false	false	true	8,649
708C	Tree is a connected acyclic graph. Suppose you are given a tree consisting of _n_ vertices. The vertex of this tree is called centroid if the size of each connected component that appears if this vertex is removed from the tree doesn't exceed . You are given a tree of size _n_ and can perform no more than one edge repl...	2,300	false	true	false	true	true	false	false	false	false	true	6,987
301E	Problem - 301E - Codeforces =============== xa0 ]( --- Finished → Virtual participation 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. If you've seen these problems, a virtual contest is not for you - s...	2,800	false	false	false	true	false	false	false	false	false	false	8,626
1864G	Aquamoon has a Rubik's Square which can be seen as an $$$n imes n$$$ matrix, the elements of the matrix constitute a permutation of numbers $$$1, ldots, n^2$$$. Aquamoon can perform two operations on the matrix: Row shift, i.e. shift an entire row of the matrix several positions (at least $$$1$$$ and at most $$$n-1$$...	3,100	false	false	true	false	false	true	false	false	false	false	1,091
367B	Problem - 367B - Codeforces =============== xa0 ]( --- Finished → Virtual participation Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests. If you've seen these problems, a virtual contest is not for you - s...	1,900	false	false	false	false	true	false	false	true	false	false	8,364
1867F	Given a tree with $$$n$$$ vertices rooted at vertex $$$1$$$, denote it as $$$G$$$. Also denote $$$P(G)$$$ as the multiset of subtrees of all vertices in tree $$$G$$$. You need to find a tree $$$G'$$$ of size $$$n$$$ rooted at vertex $$$1$$$ such that the number of subtrees in $$$P(G')$$$ that are isomorphic to any subt...	2,700	false	true	false	false	false	true	true	false	false	false	1,069

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