题目链接 题意: 给一个n*m的矩阵,每天随机的在未放棋子的格子上放一个棋子.求每行至少有一个棋子,每列至少有一个棋子的天数的期望  (1 <= N, M <= 50). 分析: 比較明显的概率DP,难点在于怎样设计状态.覆盖了多少行和列是不可缺少的,之后比較关键的就是想到还有一个属性:多少个交叉点(即放过的点) double dp[55][55][2550]; bool vis[55][55][2550]; int tot; int n, m; inline double getp(int…

Domination Time Limit: 8 Seconds      Memory Limit: 131072 KB      Special Judge 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 decorative chessboar…

Domination Time Limit: 8 Seconds      Memory Limit: 131072 KB      Special Judge 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 decorative chessboar…

3799567 2014-10-14 10:13:59                                                                     Accepted                                                             3822 C++ 1870 71760 njczy2010 3799566 2014-10-14 10:13:25                            …

Domination Time Limit: 8 Seconds      Memory Limit: 131072 KB      Special Judge 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 decorative chessboar…

Description 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 decorative chessboard with N rows and M columns. Every day after work, Edward will place…

http://acm.zju.edu.cn/onlinejudge/showContestProblems.do?contestId=358 The 2014 ACM-ICPC Asia Mudanjiang Regional Contest 136 - The 2014 ACM-ICPC Asia Mudanjiang Regional Contest Solved ID Title Ratio (AC/All) Yes A Average Score 61.78% (456/738) Yes…

主题链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do? problemId=5383 Known Notation Time Limit: 2 Seconds      Memory Limit: 65536 KB Do you know reverse Polish notation (RPN)? It is a known notation in the area of mathematics and computer science.…

The 2014 ACM-ICPC Asia Mudanjiang Regional Contest 题目链接 没去现场.做的网络同步赛.感觉还能够,搞了6题 A:这是签到题,对于A堆除掉.假设没剩余在减一.B堆直接除掉 + 1就能够了 B:二分贪心,二分长度.然后会发现本质上是在树上最长链上找两点,那么有二分出来的长度了,就从两端分别往里移动那么长,那两个位置就是放置位置.然后在推断一下就能够了 D:概率DP.首先知道放一个棋子.能够等价移动到右上角区域,那么就能够dp[x][y][k],表示…

题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=5374 思路:题目的意思是求树上的两点,使得树上其余的点到其中一个点的最长距离最小.可以想到这题与树直径有关,我们可以这样做,首先求出树的直径,然后取出树的中点以及与该中点相邻,并且是直径上的一个点,这样就把这棵树划分为两颗子树,然后分别求出这两棵树的直径,最后要选择的两个点分别就是这两棵树的直径上的中点. 一开始是用dfs写的,结果爆栈了,改成bfs就过了. #in…