CF17E-Palisection 题目: 题目描述: In an English class Nick had nothing to do at all, and remembered about wonderful strings called palindromes. We should remind you that a string is called a palindrome if it can be read the same way both from left to right and from right to left. Here are examples of such strings: «eye», «p

P1659-[国家集训队]拉拉队排练 题目: 题目描述: 艾利斯顿商学院篮球队要参加一年一度的市篮球比赛了。拉拉队是篮球比赛的一个看点，好的拉拉队

CF383C-Propagating tree 题目: 题目描述: Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of $ n $ nodes numbered from $ 1 $ to $ n $ , each node $ i $ having an initial value $ a_{i} $ . The root of the tree is node $ 1 $ . This tree has a

CF85D-Sum of Medians 题目: 题目描述: In one well-known algorithm of finding the $ k $ -th order statistics we should divide all elements into groups of five consecutive elements and find the median of each five. A median is called the middle element of a sorted array (it’s the third largest element for a group of five). To increase the algorithm’s performance speed on

CF280C-Game on Tree 题目: 题目描述: Momiji has got a rooted tree, consisting of $ n $ nodes. The tree nodes are numbered by integers from $ 1 $ to $ n $ . The root has number $ 1 $ . Momiji decided to play a game on this tree. The game consists of several steps. On each step, Momiji chooses one of the

CF19E-Fairy 题目: 题目描述: Once upon a time there lived a good fairy A. One day a fine young man B came to her and asked to predict his future. The fairy looked into her magic ball and said that soon the fine young man will meet the most beautiful princess ever and will marry her. Then she drew on a sheet of paper $