以前做过的题目了....补集+DP        Check the difficulty of problems Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 4091   Accepted: 1811 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult,…

Check the difficulty of problems Time Limit: 2000MS Memory Limit: 65536K Total Submissions: 5830 Accepted: 2542 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually expect…

Check the difficulty of problems Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 5457   Accepted: 2400 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually exp…

Check the difficulty of problems Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 4522   Accepted: 1993 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually exp…

题目链接: http://poj.org/problem?id=2151 Check the difficulty of problems Time Limit: 2000MSMemory Limit: 65536K 问题描述 Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually expect the contes…

Check the difficulty of problems Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 8903   Accepted: 3772 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually exp…

Check the difficulty of problems Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 4748   Accepted: 2078 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually exp…

有 T(1<T<=1000) 支队伍和 M(0<M<=30) 个题目,已知每支队伍 i 解决每道题目 j 的的概率 p[i][j],现在问:每支队伍至少解决一道题,且解题最多的队伍的题目数量不少于 N(0<N<=M) 的概率是多少? p[i][j]表示第i个队伍做对第j题的概率.dp[i][j][k]表示第i个队伍在前j题中做对了k道的概率.dp[i][j][k] = dp[i][j-1][k-1]*(p[i][j])+dp[i][j-1][k]*(1-p[i][j])…

http://poj.org/problem?id=2151 (题目链接) 题意 T支队伍,一共M道题,第i支队伍解出第j道题的概率为p[i][j].问每支队伍至少解出1道题并且解题最多的的队伍至少解出N道题的概率. Solution 我终于明白了,这种题目,永远也不要想着去搞清楚样例是怎么算出来的,只要列出你认为正确的dp方程就行了.. 于是这道题,令${f_{i,j,k}}$表示第i个队伍,前j道题,解出k道的概率.转移很显然: $${f_{i,j,k}=f_{i,j-1,k-1}*p_{i…

题目链接:http://poj.org/problem?id=2151 题目大意:有M个题目,T支队伍,第i个队伍做出第j个题目的概率为Pij,问每个队伍都至少做出1个题并且至少有一个队伍做出N题的概率. 先定义状态dp[i][j][k],代表第i支队伍从前j个题目里正好做出k题的概率. 有:dp[i][j][k] = dp[i][j-1][k]*(1-p[i][j]) + dp[i][j-1][k-1]*p[i][j]; 然后设f[i]为前i支队伍里,每队至少做出一个题并且至少有一个队伍做出N…