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CodeForces 3C Tic-tac-toe 井字棋盘游戏

Description The R1 company has recently bought a high rise building in the centre of Moscow for its main office. It’s time to decorate the new office, and the first thing to do is to write the company

Description Developers often face with regular expression patterns. A pattern is usually defined as a string consisting of characters and metacharacters that sets the rules for your search. These patt

Description Pasha has many hamsters and he makes them work out. Today, n hamsters (n is even) came to work out. The hamsters lined up and each hamster either sat down or stood up.For another exercise,

Description The administration of the Tomsk Region firmly believes that it’s time to become a megacity (that is, get population of one million). Instead of improving the demographic situation, they de

Description People in the Tomskaya region like magic formulas very much. You can see some of them below.Imagine you are given a sequence of positive integer numbers p1, p2, …, pn. Lets write down some

Description It’s holiday. Mashmokh and his boss, Bimokh, are playing a game invented by Mashmokh.In this game Mashmokh writes sequence of n distinct integers on the board. Then Bimokh makes several (p

Description The police department of your city has just started its journey. Initially, they don’t have any manpower. So, they started hiring new recruits in groups.Meanwhile, crimes keeps occurring w

Description The prison of your city has n prisoners. As the prison can’t accommodate all of them, the city mayor has decided to transfer c of the prisoners to a prison located in another city.For this

Description Sereja showed an interesting game to his friends. The game goes like that. Initially, there is a table with an empty cup and n water mugs on it. Then all players take turns to move. During

Description Let’s assume that we are given a matrix b of size x × y, let’s determine the operation of mirroring matrix b. The mirroring of matrix b is a 2x × y matrix c which has the following propert

Description Polycarpus develops an interesting theory about the interrelation of arithmetic progressions with just everything in the world. His current idea is that the population of the capital of Be

Description Innovation technologies are on a victorious march around the planet. They integrate into all spheres of human activity!A restaurant called “Dijkstra’s Place” has started thinking about opt

Description A well-known art union called “Kalevich is Alive!” manufactures objects d’art (pictures). The union consists of n painters who decided to organize their work as follows.Each painter uses o

Description A TV show called “Guess a number!” is gathering popularity. The whole Berland, the old and the young, are watching the show.The rules are simple. The host thinks of an integer y and the pa

Description One of the most important products of the R1 company is a popular @r1.com mail service. The R1 mailboxes receive and send millions of emails every day.Today, the online news thundered with

Description There is a right triangle with legs of length a and b. Your task is to determine whether it is possible to locate the triangle on the plane in such a way that none of its sides is parallel

DescriptionVanya loves playing. He even has a special set of cards to play with. Each card has a single integer. The number on the card can be positive, negative and can even be equal to zero. The only

DescriptionThe Queen of England has n trees growing in a row in her garden. At that, the i-th (1 ≤ i ≤ n) tree from the left has height ai meters. Today the Queen decided to update the scenery of her g

DescriptionLet’s call an undirected graph of n vertices p-interesting, if the following conditions fulfill: • the graph contains exactly 2n + p edges; • the graph doesn’t contain self-loops and mul

DescriptionYou have a nuts and lots of boxes. The boxes have a wonderful feature: if you put x(x ≥ 0) divisors (the spacial bars that can divide a box) to it, you get a box, divided into x + 1 sections

DescriptionInna loves sleeping very much, so she needs n alarm clocks in total to wake up. Let’s suppose that Inna’s room is a 100 × 100 square with the lower left corner at point (0, 0) and with the u

DescriptionFox Ciel is playing a game with numbers now. Ciel has n positive integers: x1, x2, …, xn. She can do the following operation as many times as needed: select two different indexes i and j suc

DescriptionFox Ciel has a board with n rows and n columns. So, the board consists of n × n cells. Each cell contains either a symbol ‘.’, or a symbol ‘#’.A cross on the board is a connected set of exac

SubmitStatusDescriptionInna is a great piano player and Dima is a modest guitar player. Dima has recently written a song and they want to play it together. Of course, Sereja wants to listen to the song

DescriptionInna likes sweets and a game called the “Candy Matrix”. Today, she came up with the new game “Candy Matrix 2: Reload”.The field for the new game is a rectangle table of size n × m. Each line

DescriptionThere always is something to choose from! And now, instead of “Noughts and Crosses”, Inna choose a very unusual upgrade of this game. The rules of the game are given below:There is one perso

DescriptionInna and Dima decided to surprise Sereja. They brought a really huge candy matrix, it’s big even for Sereja! Let’s number the rows of the giant matrix from 1 to n from top to bottom and the

Description One day, at the “Russian Code Cup” event it was decided to play football as an out of competition event. All participants was divided into n teams and played several matches, two teams cou

Description During the “Russian Code Cup” programming competition, the testing system stores all sent solutions for each participant. We know that many participants use random numbers in their program

Description While resting on the ship after the “Russian Code Cup” a boy named Misha invented an interesting game. He promised to give his quadrocopter to whoever will be the first one to make a recta

Description The finalists of the “Russian Code Cup” competition in 2214 will be the participants who win in one of the elimination rounds.The elimination rounds are divided into main and additional. E