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蜜汁打表题、、 (首先L=1和L=N的情况过于傻逼(而且是特殊情况)，可以先写出来，然后剩下的L的做法在下面) 首先你要写一个打表程序，找出{1,2,....,n} 乘若干个 循环唯一的轮换可以搞出的所有排列，然后统计一下对于每个i，总环数=i 的排列的个数 cnt[i]。 如果你规律找的好的话，是 阅读全文
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Problem Statement One day, Takahashi was given the following problem from Aoki: You are given a tree with N vertices and an integer K. The vertices ar 阅读全文
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Problem Statement You are participating in a quiz with N+M questions and Yes/No answers. It's known in advance that there are N questions with answer 阅读全文
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Discription Arkady's code contains nn variables. Each variable has a unique name consisting of lowercase English letters only. One day Arkady decided 阅读全文
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简单最短路计数。 阅读全文