摘要： 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 阅读全文

摘要： Daniel has a string s, consisting of lowercase English letters and period signs (characters '.'). Let's define the operation of replacement as the fol 阅读全文

摘要： output standard output output standard output output Ohana Matsumae is trying to clean a room, which is divided up into an n by n grid of squares. Eac 阅读全文

摘要： Permutation p is an ordered set of integers p1, p2, ..., pn, consisting of n distinct positive integers not larger than n. We'll denote as n the lengt 阅读全文

摘要： Quite recently a creative student Lesha had a lecture on trees. After the lecture Lesha was inspired and came up with the tree of his own which he cal 阅读全文

摘要： Peter Parker wants to play a game with Dr. Octopus. The game is about cycles. Cycle is a sequence of vertices, such that first one is connected with t 阅读全文

摘要： Caisa is going to have a party and he needs to buy the ingredients for a big chocolate cake. For that he is going to the biggest supermarket in town. 阅读全文

摘要： Vasya has the square chessboard of size n × n and m rooks. Initially the chessboard is empty. Vasya will consequently put the rooks on the board one a 阅读全文

摘要： DZY loves chessboard, and he enjoys playing with it. He has a chessboard of n rows and m columns. Some cells of the chessboard are bad, others are goo 阅读全文

摘要： Fedya studies in a gymnasium. Fedya's maths hometask is to calculate the following expression: (1^n + 2^n + 3^n + 4^n) mod 5 for given value of n. Fed 阅读全文