脂环

摘要： For the given integer nn (n>2n>2 ) let's write down all the strings of length nn which contain n−2n−2 letters 'a' and two letters 'b' in lexicographic 阅读全文

摘要： You are given two positive integers aa and bb. In one move you can increase aa by 11 (replace aa with a+1a+1). Your task is to find the minimum number 阅读全文

摘要： Trees are an important component of the natural landscape because of their prevention of erosion and the provision of a specific ather-sheltered ecosy 阅读全文

摘要： 题目描述 有一棵苹果树，如果树枝有分叉，一定是分2叉（就是说没有只有1个儿子的结点） 这棵树共有N个结点（叶子点或者树枝分叉点），编号为1-N,树根编号一定是1。 我们用一根树枝两端连接的结点的编号来描述一根树枝的位置。下面是一颗有4个树枝的树 2 5 \ / 3 4 \ / 1 现在这颗树枝条太多 阅读全文

摘要： 题目描述 小明对数学饱有兴趣，并且是个勤奋好学的学生，总是在课后留在教室向老师请教一些问题。一天他早晨骑车去上课，路上见到一个老伯正在修剪花花草草，顿时想到了一个有关修剪花卉的问题。于是当日课后，小明就向老师提出了这个问题： 一株奇怪的花卉，上面共连有NN N朵花，共有N−1N-1N−1条枝干将花儿 阅读全文

摘要： 题目描述 一场可怕的地震后，人们用N个牲口棚(1≤N≤150，编号1..N)重建了农夫John的牧场。由于人们没有时间建设多余的道路，所以现在从一个牲口棚到另一个牲口棚的道路是惟一的。因此，牧场运输系统可以被构建成一棵树。John想要知道另一次地震会造成多严重的破坏。有些道路一旦被毁坏，就会使一棵含 阅读全文

摘要： E. Count The Blocks time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You wrote down all i 阅读全文

摘要： Petya has a rectangular Board of size n×mn×m . Initially, kk chips are placed on the board, ii -th chip is located in the cell at the intersection of 阅读全文

摘要： The King of Berland Polycarp LXXXIV has nn daughters. To establish his power to the neighbouring kingdoms he wants to marry his daughters to the princ 阅读全文

摘要： You are given two integers nn and kk. Your task is to find if nn can be represented as a sum of kk distinct positive odd (not divisible by 22) integer 阅读全文