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apps_data_2000
Codefortia is a small island country located somewhere in the West Pacific. It consists of $n$ settlements connected by $m$ bidirectional gravel roads. Curiously enough, the beliefs of the inhabitants require the time needed to pass each road to be equal either to $a$ or $b$ seconds. It's guaranteed that one can go bet...
apps_data_2001
Pikachu had an array with him. He wrote down all the non-empty subsequences of the array on paper. Note that an array of size n has 2^{n} - 1 non-empty subsequences in it. Pikachu being mischievous as he always is, removed all the subsequences in which Maximum_element_of_the_subsequence - Minimum_element_of_subsequ...
apps_data_2002
Vasya and Kolya play a game with a string, using the following rules. Initially, Kolya creates a string s, consisting of small English letters, and uniformly at random chooses an integer k from a segment [0, len(s) - 1]. He tells Vasya this string s, and then shifts it k letters to the left, i. e. creates a new string ...
apps_data_2003
In the evenings Donkey would join Shrek to look at the stars. They would sit on a log, sipping tea and they would watch the starry sky. The sky hung above the roof, right behind the chimney. Shrek's stars were to the right of the chimney and the Donkey's stars were to the left. Most days the Donkey would just count the...
apps_data_2004
The Little Elephant has an integer a, written in the binary notation. He wants to write this number on a piece of paper. To make sure that the number a fits on the piece of paper, the Little Elephant ought to delete exactly one any digit from number a in the binary record. At that a new number appears. It consists of ...
apps_data_2005
Toad Rash has a binary string $s$. A binary string consists only of zeros and ones. Let $n$ be the length of $s$. Rash needs to find the number of such pairs of integers $l$, $r$ that $1 \leq l \leq r \leq n$ and there is at least one pair of integers $x$, $k$ such that $1 \leq x, k \leq n$, $l \leq x < x + 2k \leq r...
apps_data_2006
It is so boring in the summer holiday, isn't it? So Alice and Bob have invented a new game to play. The rules are as follows. First, they get a set of n distinct integers. And then they take turns to make the following moves. During each move, either Alice or Bob (the player whose turn is the current) can choose two di...
apps_data_2007
Mad scientist Mike does not use slow hard disks. His modification of a hard drive has not one, but n different heads that can read data in parallel. When viewed from the side, Mike's hard drive is an endless array of tracks. The tracks of the array are numbered from left to right with integers, starting with 1. In the...
apps_data_2008
A schoolboy named Vasya loves reading books on programming and mathematics. He has recently read an encyclopedia article that described the method of median smoothing (or median filter) and its many applications in science and engineering. Vasya liked the idea of the method very much, and he decided to try it in practi...
apps_data_2009
For a vector $\vec{v} = (x, y)$, define $|v| = \sqrt{x^2 + y^2}$. Allen had a bit too much to drink at the bar, which is at the origin. There are $n$ vectors $\vec{v_1}, \vec{v_2}, \cdots, \vec{v_n}$. Allen will make $n$ moves. As Allen's sense of direction is impaired, during the $i$-th move he will either move in th...
apps_data_2010
Limak is a little bear who loves to play. Today he is playing by destroying block towers. He built n towers in a row. The i-th tower is made of h_{i} identical blocks. For clarification see picture for the first sample. Limak will repeat the following operation till everything is destroyed. Block is called internal i...
apps_data_2011
Eighth-grader Vova is on duty today in the class. After classes, he went into the office to wash the board, and found on it the number n. He asked what is this number and the teacher of mathematics Inna Petrovna answered Vova that n is the answer to the arithmetic task for first-graders. In the textbook, a certain posi...
apps_data_2012
A permutation p of size n is the sequence p_1, p_2, ..., p_{n}, consisting of n distinct integers, each of them is from 1 to n (1 ≤ p_{i} ≤ n). A lucky permutation is such permutation p, that any integer i (1 ≤ i ≤ n) meets this condition p_{p}_{i} = n - i + 1. You have integer n. Find some lucky permutation p of siz...
apps_data_2013
You are given a non-empty string s consisting of lowercase English letters. You have to pick exactly one non-empty substring of s and shift all its letters 'z' $\rightarrow$ 'y' $\rightarrow$ 'x' $\rightarrow \ldots \rightarrow$ 'b' $\rightarrow$ 'a' $\rightarrow$ 'z'. In other words, each character is replaced with th...
apps_data_2014
After a wonderful evening in the restaurant the time to go home came. Leha as a true gentlemen suggested Noora to give her a lift. Certainly the girl agreed with pleasure. Suddenly one problem appeared: Leha cannot find his car on a huge parking near the restaurant. So he decided to turn to the watchman for help. Form...
apps_data_2015
Gennady is one of the best child dentists in Berland. Today n children got an appointment with him, they lined up in front of his office. All children love to cry loudly at the reception at the dentist. We enumerate the children with integers from 1 to n in the order they go in the line. Every child is associated with...
apps_data_2016
Alex decided to go on a touristic trip over the country. For simplicity let's assume that the country has $n$ cities and $m$ bidirectional roads connecting them. Alex lives in city $s$ and initially located in it. To compare different cities Alex assigned each city a score $w_i$ which is as high as interesting city se...
apps_data_2017
Allen is hosting a formal dinner party. $2n$ people come to the event in $n$ pairs (couples). After a night of fun, Allen wants to line everyone up for a final picture. The $2n$ people line up, but Allen doesn't like the ordering. Allen prefers if each pair occupies adjacent positions in the line, as this makes the pic...
apps_data_2018
This problem is the most boring one you've ever seen. Given a sequence of integers a_1, a_2, ..., a_{n} and a non-negative integer h, our goal is to partition the sequence into two subsequences (not necessarily consist of continuous elements). Each element of the original sequence should be contained in exactly one o...
apps_data_2019
One day n friends gathered together to play "Mafia". During each round of the game some player must be the supervisor and other n - 1 people take part in the game. For each person we know in how many rounds he wants to be a player, not the supervisor: the i-th person wants to play a_{i} rounds. What is the minimum numb...
apps_data_2020
Ivan wants to make a necklace as a present to his beloved girl. A necklace is a cyclic sequence of beads of different colors. Ivan says that necklace is beautiful relative to the cut point between two adjacent beads, if the chain of beads remaining after this cut is a palindrome (reads the same forward and backward). ...
apps_data_2021
Recently, Pari and Arya did some research about NP-Hard problems and they found the minimum vertex cover problem very interesting. Suppose the graph G is given. Subset A of its vertices is called a vertex cover of this graph, if for each edge uv there is at least one endpoint of it in this set, i.e. $u \in A$ or $v \i...
apps_data_2022
Students went into a class to write a test and sat in some way. The teacher thought: "Probably they sat in this order to copy works of each other. I need to rearrange them in such a way that students that were neighbors are not neighbors in a new seating." The class can be represented as a matrix with n rows and m col...
apps_data_2023
Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smith remembered was that any permutation of $n$ can be a secret phone number. Only those permutations that minimize secret value might be the phone of her husband. The sequence of $n$ integers is call...
apps_data_2024
You're playing a game called Osu! Here's a simplified version of it. There are n clicks in a game. For each click there are two outcomes: correct or bad. Let us denote correct as "O", bad as "X", then the whole play can be encoded as a sequence of n characters "O" and "X". Using the play sequence you can calculate the...
apps_data_2025
Vasya and Petya are playing a simple game. Vasya thought of number x between 1 and n, and Petya tries to guess the number. Petya can ask questions like: "Is the unknown number divisible by number y?". The game is played by the following rules: first Petya asks all the questions that interest him (also, he can ask no ...
apps_data_2026
Yaroslav is playing a game called "Time". The game has a timer showing the lifespan he's got left. As soon as the timer shows 0, Yaroslav's character dies and the game ends. Also, the game has n clock stations, station number i is at point (x_{i}, y_{i}) of the plane. As the player visits station number i, he increases...
apps_data_2027
Squirrel Liss lived in a forest peacefully, but unexpected trouble happens. Stones fall from a mountain. Initially Squirrel Liss occupies an interval [0, 1]. Next, n stones will fall and Liss will escape from the stones. The stones are numbered from 1 to n in order. The stones always fall to the center of Liss's inter...
apps_data_2028
Reading books is one of Sasha's passions. Once while he was reading one book, he became acquainted with an unusual character. The character told about himself like that: "Many are my names in many countries. Mithrandir among the Elves, Tharkûn to the Dwarves, Olórin I was in my youth in the West that is forgotten, in t...
apps_data_2029
You are given integer $n$. You have to arrange numbers from $1$ to $2n$, using each of them exactly once, on the circle, so that the following condition would be satisfied: For every $n$ consecutive numbers on the circle write their sum on the blackboard. Then any two of written on the blackboard $2n$ numbers differ n...
apps_data_2030
A group of n cities is connected by a network of roads. There is an undirected road between every pair of cities, so there are $\frac{n \cdot(n - 1)}{2}$ roads in total. It takes exactly y seconds to traverse any single road. A spanning tree is a set of roads containing exactly n - 1 roads such that it's possible to t...
apps_data_2031
Dreamoon likes coloring cells very much. There is a row of $n$ cells. Initially, all cells are empty (don't contain any color). Cells are numbered from $1$ to $n$. You are given an integer $m$ and $m$ integers $l_1, l_2, \ldots, l_m$ ($1 \le l_i \le n$) Dreamoon will perform $m$ operations. In $i$-th operation, Dre...
apps_data_2032
Vanya wants to minimize a tree. He can perform the following operation multiple times: choose a vertex v, and two disjoint (except for v) paths of equal length a_0 = v, a_1, ..., a_{k}, and b_0 = v, b_1, ..., b_{k}. Additionally, vertices a_1, ..., a_{k}, b_1, ..., b_{k} must not have any neighbours in the tree other t...
apps_data_2033
Sasha is taking part in a programming competition. In one of the problems she should check if some rooted trees are isomorphic or not. She has never seen this problem before, but, being an experienced participant, she guessed that she should match trees to some sequences and then compare these sequences instead of tree...
apps_data_2034
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 between two points $p...
apps_data_2035
This is the easy version of the problem. The only difference between easy and hard versions is the constraint of $m$. You can make hacks only if both versions are solved. Chiori loves dolls and now she is going to decorate her bedroom![Image]  As a doll collector, Chiori has got $n$ dolls. The $i$-th doll has a non-n...
apps_data_2036
The biggest event of the year – Cota 2 world championship "The Innernational" is right around the corner. $2^n$ teams will compete in a double-elimination format (please, carefully read problem statement even if you know what is it) to identify the champion. Teams are numbered from $1$ to $2^n$ and will play games on...
apps_data_2037
You work in a big office. It is a 9 floor building with an elevator that can accommodate up to 4 people. It is your responsibility to manage this elevator. Today you are late, so there are queues on some floors already. For each person you know the floor where he currently is and the floor he wants to reach. Also, you...
apps_data_2038
Logical quantifiers are very useful tools for expressing claims about a set. For this problem, let's focus on the set of real numbers specifically. The set of real numbers includes zero and negatives. There are two kinds of quantifiers: universal ($\forall$) and existential ($\exists$). You can read more about them her...
apps_data_2039
Toad Zitz has an array of integers, each integer is between $0$ and $m-1$ inclusive. The integers are $a_1, a_2, \ldots, a_n$. In one operation Zitz can choose an integer $k$ and $k$ indices $i_1, i_2, \ldots, i_k$ such that $1 \leq i_1 < i_2 < \ldots < i_k \leq n$. He should then change $a_{i_j}$ to $((a_{i_j}+1) \bm...
apps_data_2040
Igor the analyst has adopted n little bunnies. As we all know, bunnies love carrots. Thus, Igor has bought a carrot to be shared between his bunnies. Igor wants to treat all the bunnies equally, and thus he wants to cut the carrot into n pieces of equal area. Formally, the carrot can be viewed as an isosceles triangl...
apps_data_2041
The life goes up and down, just like nice sequences. Sequence t_1, t_2, ..., t_{n} is called nice if the following two conditions are satisfied: t_{i} < t_{i} + 1 for each odd i < n; t_{i} > t_{i} + 1 for each even i < n. For example, sequences (2, 8), (1, 5, 1) and (2, 5, 1, 100, 99, 120) are nice, while (1, 1), ...
apps_data_2042
Vasya's telephone contains n photos. Photo number 1 is currently opened on the phone. It is allowed to move left and right to the adjacent photo by swiping finger over the screen. If you swipe left from the first photo, you reach photo n. Similarly, by swiping right from the last photo you reach photo 1. It takes a sec...
apps_data_2043
Doubly linked list is one of the fundamental data structures. A doubly linked list is a sequence of elements, each containing information about the previous and the next elements of the list. In this problem all lists have linear structure. I.e. each element except the first has exactly one previous element, each eleme...
apps_data_2044
Arkady needs your help again! This time he decided to build his own high-speed Internet exchange point. It should consist of n nodes connected with minimum possible number of wires into one network (a wire directly connects two nodes). Exactly k of the nodes should be exit-nodes, that means that each of them should be ...
apps_data_2045
Hooray! Berl II, the king of Berland is making a knight tournament. The king has already sent the message to all knights in the kingdom and they in turn agreed to participate in this grand event. As for you, you're just a simple peasant. There's no surprise that you slept in this morning and were late for the tourname...
apps_data_2046
Farmer John has just given the cows a program to play with! The program contains two integer variables, x and y, and performs the following operations on a sequence a_1, a_2, ..., a_{n} of positive integers: Initially, x = 1 and y = 0. If, after any step, x ≤ 0 or x > n, the program immediately terminates. The progra...
apps_data_2047
Allen dreams of one day owning a enormous fleet of electric cars, the car of the future! He knows that this will give him a big status boost. As Allen is planning out all of the different types of cars he will own and how he will arrange them, he realizes that he has a problem. Allen's future parking lot can be repre...
apps_data_2048
We all know the impressive story of Robin Hood. Robin Hood uses his archery skills and his wits to steal the money from rich, and return it to the poor. There are n citizens in Kekoland, each person has c_{i} coins. Each day, Robin Hood will take exactly 1 coin from the richest person in the city and he will give it t...
apps_data_2049
Bob recently read about bitwise operations used in computers: AND, OR and XOR. He have studied their properties and invented a new game. Initially, Bob chooses integer m, bit depth of the game, which means that all numbers in the game will consist of m bits. Then he asks Peter to choose some m-bit number. After that, ...
apps_data_2050
Andrew, Fedor and Alex are inventive guys. Now they invent the game with strings for two players. Given a group of n non-empty strings. During the game two players build the word together, initially the word is empty. The players move in turns. On his step player must add a single letter in the end of the word, the re...
apps_data_2051
Helen works in Metropolis airport. She is responsible for creating a departure schedule. There are n flights that must depart today, the i-th of them is planned to depart at the i-th minute of the day. Metropolis airport is the main transport hub of Metropolia, so it is difficult to keep the schedule intact. This is e...
apps_data_2052
Gerald plays the following game. He has a checkered field of size n × n cells, where m various cells are banned. Before the game, he has to put a few chips on some border (but not corner) board cells. Then for n - 1 minutes, Gerald every minute moves each chip into an adjacent cell. He moves each chip from its original...
apps_data_2053
$n$ boys and $m$ girls came to the party. Each boy presented each girl some integer number of sweets (possibly zero). All boys are numbered with integers from $1$ to $n$ and all girls are numbered with integers from $1$ to $m$. For all $1 \leq i \leq n$ the minimal number of sweets, which $i$-th boy presented to some g...
apps_data_2054
Each New Year Timofey and his friends cut down a tree of n vertices and bring it home. After that they paint all the n its vertices, so that the i-th vertex gets color c_{i}. Now it's time for Timofey birthday, and his mother asked him to remove the tree. Timofey removes the tree in the following way: he takes some ve...
apps_data_2055
Andrew and Eugene are playing a game. Initially, Andrew has string s, consisting of digits. Eugene sends Andrew multiple queries of type "d_{i} → t_{i}", that means "replace all digits d_{i} in string s with substrings equal to t_{i}". For example, if s = 123123, then query "2 → 00" transforms s to 10031003, and query ...
apps_data_2056
You are given two binary strings $a$ and $b$ of the same length. You can perform the following two operations on the string $a$: Swap any two bits at indices $i$ and $j$ respectively ($1 \le i, j \le n$), the cost of this operation is $|i - j|$, that is, the absolute difference between $i$ and $j$. Select any arbit...
apps_data_2057
We have a string of letters 'a' and 'b'. We want to perform some operations on it. On each step we choose one of substrings "ab" in the string and replace it with the string "bba". If we have no "ab" as a substring, our job is done. Print the minimum number of steps we should perform to make our job done modulo 10^9 + ...
apps_data_2058
Sonya was unable to think of a story for this problem, so here comes the formal description. You are given the array containing n positive integers. At one turn you can pick any element and increase or decrease it by 1. The goal is the make the array strictly increasing by making the minimum possible number of operati...
apps_data_2059
Jeff's friends know full well that the boy likes to get sequences and arrays for his birthday. Thus, Jeff got sequence p_1, p_2, ..., p_{n} for his birthday. Jeff hates inversions in sequences. An inversion in sequence a_1, a_2, ..., a_{n} is a pair of indexes i, j (1 ≤ i < j ≤ n), such that an inequality a_{i} > a_{j...
apps_data_2060
Evlampiy has found one more cool application to process photos. However the application has certain limitations. Each photo i has a contrast v_{i}. In order for the processing to be truly of high quality, the application must receive at least k photos with contrasts which differ as little as possible. Evlampiy alread...
apps_data_2061
We have three stones at points (0, 0), (1,0), and (0,1) on a two-dimensional plane. These three stones are said to form an L when they satisfy the following conditions: - Each of the stones is at integer coordinates. - Each of the stones is adjacent to another stone. (That is, for each stone, there is another stone w...
apps_data_2062
There are N people, conveniently numbered 1 through N. We want to divide them into some number of groups, under the following two conditions: - Every group contains between A and B people, inclusive. - Let F_i be the number of the groups containing exactly i people. Then, for all i, either F_i=0 or C≤F_i≤D holds. Fin...
apps_data_2063
The "BerCorp" company has got n employees. These employees can use m approved official languages for the formal correspondence. The languages are numbered with integers from 1 to m. For each employee we have the list of languages, which he knows. This list could be empty, i. e. an employee may know no official language...
apps_data_2064
3R2 as DJ Mashiro - Happiness Breeze Ice - DJ Mashiro is dead or alive NEKO#ΦωΦ has just got a new maze game on her PC! The game's main puzzle is a maze, in the forms of a $2 \times n$ rectangle grid. NEKO's task is to lead a Nekomimi girl from cell $(1, 1)$ to the gate at $(2, n)$ and escape the maze. The girl can o...
apps_data_2065
Andrewid the Android is a galaxy-famous detective. He is now investigating the case of vandalism at the exhibition of contemporary art. The main exhibit is a construction of n matryoshka dolls that can be nested one into another. The matryoshka dolls are numbered from 1 to n. A matryoshka with a smaller number can be ...
apps_data_2066
In the official contest this problem has a different statement, for which jury's solution was working incorrectly, and for this reason it was excluded from the contest. This mistake have been fixed and the current given problem statement and model solution corresponds to what jury wanted it to be during the contest. V...
apps_data_2067
One Big Software Company has n employees numbered from 1 to n. The director is assigned number 1. Every employee of the company except the director has exactly one immediate superior. The director, of course, doesn't have a superior. We will call person a a subordinates of another person b, if either b is an immediate...
apps_data_2068
The Fair Nut is going to travel to the Tree Country, in which there are $n$ cities. Most of the land of this country is covered by forest. Furthermore, the local road system forms a tree (connected graph without cycles). Nut wants to rent a car in the city $u$ and go by a simple path to city $v$. He hasn't determined t...
apps_data_2069
You are given an array $a$ of $n$ integers. You want to make all elements of $a$ equal to zero by doing the following operation exactly three times: Select a segment, for each number in this segment we can add a multiple of $len$ to it, where $len$ is the length of this segment (added integers can be different). It...
apps_data_2070
Karen has just arrived at school, and she has a math test today! [Image] 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. Th...
apps_data_2071
Watchmen are in a danger and Doctor Manhattan together with his friend Daniel Dreiberg should warn them as soon as possible. There are n watchmen on a plane, the i-th watchman is located at point (x_{i}, y_{i}). They need to arrange a plan, but there are some difficulties on their way. As you know, Doctor Manhattan co...
apps_data_2072
Edo has got a collection of n refrigerator magnets! He decided to buy a refrigerator and hang the magnets on the door. The shop can make the refrigerator with any size of the door that meets the following restrictions: the refrigerator door must be rectangle, and both the length and the width of the door must be posit...
apps_data_2073
Bike loves looking for the second maximum element in the sequence. The second maximum element in the sequence of distinct numbers x_1, x_2, ..., x_{k} (k > 1) is such maximum element x_{j}, that the following inequality holds: $x_{j} \neq \operatorname{max}_{i = 1}^{k} x_{i}$. The lucky number of the sequence of disti...
apps_data_2074
You've got array A, consisting of n integers and a positive integer k. Array A is indexed by integers from 1 to n. You need to permute the array elements so that value $\sum_{i = 1}^{n - k}|A [ i ] - A [ i + k ]|$ became minimal possible. In particular, it is allowed not to change order of elements at all. -----Inpu...
apps_data_2075
It is known that there are k fish species in the polar ocean, numbered from 1 to k. They are sorted by non-decreasing order of their weight, which is a positive number. Let the weight of the i-th type of fish be w_{i}, then 0 < w_1 ≤ w_2 ≤ ... ≤ w_{k} holds. Polar bears Alice and Bob each have caught some fish, and th...
apps_data_2076
You are given set of n points in 5-dimensional space. The points are labeled from 1 to n. No two points coincide. We will call point a bad if there are different points b and c, not equal to a, from the given set such that angle between vectors $\vec{ab}$ and $\vec{ac}$ is acute (i.e. strictly less than $90^{\circ}$)....
apps_data_2077
Little X has n distinct integers: p_1, p_2, ..., p_{n}. He wants to divide all of them into two sets A and B. The following two conditions must be satisfied: If number x belongs to set A, then number a - x must also belong to set A. If number x belongs to set B, then number b - x must also belong to set B. Help Lit...
apps_data_2078
One player came to a casino and found a slot machine where everything depends only on how he plays. The rules follow. A positive integer $a$ is initially on the screen. The player can put a coin into the machine and then add $1$ to or subtract $1$ from any two adjacent digits. All digits must remain from $0$ to $9$ af...
apps_data_2079
Barney lives in NYC. NYC has infinite number of intersections numbered with positive integers starting from 1. There exists a bidirectional road between intersections i and 2i and another road between i and 2i + 1 for every positive integer i. You can clearly see that there exists a unique shortest path between any two...
apps_data_2080
Maxim always goes to the supermarket on Sundays. Today the supermarket has a special offer of discount systems. There are m types of discounts. We assume that the discounts are indexed from 1 to m. To use the discount number i, the customer takes a special basket, where he puts exactly q_{i} items he buys. Under the t...
apps_data_2081
Nikita likes tasks on order statistics, for example, he can easily find the $k$-th number in increasing order on a segment of an array. But now Nikita wonders how many segments of an array there are such that a given number $x$ is the $k$-th number in increasing order on this segment. In other words, you should find th...
apps_data_2082
Slime and his $n$ friends are at a party. Slime has designed a game for his friends to play. At the beginning of the game, the $i$-th player has $a_i$ biscuits. At each second, Slime will choose a biscuit randomly uniformly among all $a_1 + a_2 + \ldots + a_n$ biscuits, and the owner of this biscuit will give it to a ...
apps_data_2083
Levko loves array a_1, a_2, ... , a_{n}, consisting of integers, very much. That is why Levko is playing with array a, performing all sorts of operations with it. Each operation Levko performs is of one of two types: Increase all elements from l_{i} to r_{i} by d_{i}. In other words, perform assignments a_{j} = a_{j...
apps_data_2084
Once Vasya and Petya assembled a figure of m cubes, each of them is associated with a number between 0 and m - 1 (inclusive, each number appeared exactly once). Let's consider a coordinate system such that the OX is the ground, and the OY is directed upwards. Each cube is associated with the coordinates of its lower le...
apps_data_2085
You are given n strings s_1, s_2, ..., s_{n} consisting of characters 0 and 1. m operations are performed, on each of them you concatenate two existing strings into a new one. On the i-th operation the concatenation s_{a}_{i}s_{b}_{i} is saved into a new string s_{n} + i (the operations are numbered starting from 1). A...
apps_data_2086
Recently, on the course of algorithms and data structures, Valeriy learned how to use a deque. He built a deque filled with $n$ elements. The $i$-th element is $a_i$ ($i$ = $1, 2, \ldots, n$). He gradually takes the first two leftmost elements from the deque (let's call them $A$ and $B$, respectively), and then does th...
apps_data_2087
Vasya has n items lying in a line. The items are consecutively numbered by numbers from 1 to n in such a way that the leftmost item has number 1, the rightmost item has number n. Each item has a weight, the i-th item weights w_{i} kilograms. Vasya needs to collect all these items, however he won't do it by himself. He...
apps_data_2088
Genos recently installed the game Zuma on his phone. In Zuma there exists a line of n gemstones, the i-th of which has color c_{i}. The goal of the game is to destroy all the gemstones in the line as quickly as possible. In one second, Genos is able to choose exactly one continuous substring of colored gemstones that ...
apps_data_2089
Petya learned a new programming language CALPAS. A program in this language always takes one non-negative integer and returns one non-negative integer as well. In the language, there are only three commands: apply a bitwise operation AND, OR or XOR with a given constant to the current integer. A program can contain an...
apps_data_2090
In some country there are exactly n cities and m bidirectional roads connecting the cities. Cities are numbered with integers from 1 to n. If cities a and b are connected by a road, then in an hour you can go along this road either from city a to city b, or from city b to city a. The road network is such that from any ...
apps_data_2091
Sereja has a bracket sequence s_1, s_2, ..., s_{n}, or, in other words, a string s of length n, consisting of characters "(" and ")". Sereja needs to answer m queries, each of them is described by two integers l_{i}, r_{i} (1 ≤ l_{i} ≤ r_{i} ≤ n). The answer to the i-th query is the length of the maximum correct brack...
apps_data_2092
There are literally dozens of snooker competitions held each year, and team Jinotega tries to attend them all (for some reason they prefer name "snookah")! When a competition takes place somewhere far from their hometown, Ivan, Artsem and Konstantin take a flight to the contest and back. Jinotega's best friends, team ...
apps_data_2093
Ivan has an array consisting of n different integers. He decided to reorder all elements in increasing order. Ivan loves merge sort so he decided to represent his array with one or several increasing sequences which he then plans to merge into one sorted array. Ivan represent his array with increasing sequences with h...
apps_data_2094
When Serezha was three years old, he was given a set of cards with letters for his birthday. They were arranged into words in the way which formed the boy's mother favorite number in binary notation. Serezha started playing with them immediately and shuffled them because he wasn't yet able to read. His father decided t...
apps_data_2095
A tree is an undirected connected graph without cycles. Let's consider a rooted undirected tree with n vertices, numbered 1 through n. There are many ways to represent such a tree. One way is to create an array with n integers p_1, p_2, ..., p_{n}, where p_{i} denotes a parent of vertex i (here, for convenience a root...
apps_data_2096
You are given a sequence a_1, a_2, ..., a_{n} consisting of different integers. It is required to split this sequence into the maximum number of subsequences such that after sorting integers in each of them in increasing order, the total sequence also will be sorted in increasing order. Sorting integers in a subsequen...
apps_data_2097
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, y) (1 ≤ x, y ≤ n) as the longest edge in the shortest path between nodes x and y. Specially g(z, z) = 0 for every...
apps_data_2098
As you know, majority of students and teachers of Summer Informatics School live in Berland for the most part of the year. Since corruption there is quite widespread, the following story is not uncommon. Elections are coming. You know the number of voters and the number of parties — $n$ and $m$ respectively. For each ...
apps_data_2099
Permutation p is an ordered set of integers p_1, p_2, ..., p_{n}, consisting of n distinct positive integers not larger than n. We'll denote as n the length of permutation p_1, p_2, ..., p_{n}. Your task is to find such permutation p of length n, that the group of numbers |p_1 - p_2|, |p_2 - p_3|, ..., |p_...