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题目链接：http://codeforces.com/contest/934/problem/C 因为最后要找的是一段单调非减区间，所以最后形成的序列一定是11...12....22。中间有一个从1到2的断点。 现在要找一个区间反转，如果反转之后形成的序列的断点不在这个区间内，那么这次反转就没有任何 阅读全文
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Edward is the headmaster of Marjar University. He is enthusiastic about chess and often plays chess with his friends. What's more, he bought a large d 阅读全文
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Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids labeled from 0 to N. Hzz starts at grid 0. For each step he 阅读全文
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Problem Description Akemi Homura is a Mahou Shoujo (Puella Magi/Magical Girl).Homura wants to help her friend Madoka save the world. But because of th 阅读全文
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Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Iv 阅读全文
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Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually expect the contest 阅读全文
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有2^n个人进行比赛，所以可以推出比赛共需要进行n轮，单独考虑第n轮中序号为i的人需要面对的潜在对手，将这些对手分别考虑。 转移方程为dp[i][j]+=dp[k][j-1]*dp[i][j-1]*a[i][k];即晋级的概率=∑（自己来到这一轮的概率*对手来到这一轮的概率*战胜对手的概率） 阅读全文
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概率dp入门题，转移方程为dp[i]=dp[i-1]*p+dp[i-2]*(1-p) 因为n个数字上限很大，所以常规的概率dp基本不可能，要用矩阵优化。 把路程分成n+1段，分别计算通过每段的成功率，即刚好跨越地雷的概率（dp[地雷x+1]） 算好每段之后把每段的成功率相乘。 （若有两颗地雷相邻那么 阅读全文
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矩阵快速幂模板（手撸一遍，一下午修改的头要爆炸了！！！！！！！） 果然是菜原罪╮(╯▽╰)╭ 阅读全文
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Description Imagine you are standing inside a two-dimensional maze composed of square cells which may or may not be filled with rock. You can move nor 阅读全文