摘要：D. Substringtime limit per test3 secondsYou are given a graph with n nodes and m directed edges. One lowercase letter is assigned to each node. We def 阅读全文

摘要：Descriptionn场不同的比赛，派k个人去，一个人可以参加多场比赛且至少参加一场，每场比赛只能且必须要有一个人参加，问方案数Input第一行一整数T表示用例组数，每组用例输入两个整数n和k分别表示比赛数和人数(1<=k<=1e6,1<=n<=1e3)Output输出方案数Sample Inpu 阅读全文

摘要：For example, when she see a number, she would think whether the digits of a number are strictly increasing. If you consider the number as a string and 阅读全文

摘要：C.Two ArraysYou are given two integers n and m. Calculate the number of pairs of arrays (a,b) such that: the length of both arrays is equal to m;each 阅读全文