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…

题意 某场比赛有M道问题,T支队伍,和数字N给出每支队伍解决每道问题的概率. 问这场比赛满足下面两个条件的概率 1.每支队伍至少做出一道题 2.冠军队至少做出N道题. 分析 条件2是不是可以转化为 至少有一支队做出N道及以上道题. 这个题主要是概率,其次才是dp,而且好像不算概率DP. 我们来倒推一下. 设p2为每支队伍做出来的题数都在(1-N-1)的概率.p1为每只队伍至少做出来一道题的概率.那么答案就是p1-p2. 然后我们再来想怎么求p1和p2.设s[i][j]为第i支队伍做出来题数小于等…

概率DP kuangbin总结中的第8题 一开始题目看错导致想转移方程想错了……想成f[i][j]表示前 i 个队伍中最多的做出来 j 道题的概率……sigh 看了下题解……其实是对于每个队伍 i 单独考虑做出来 j 道题的概率!!最后再根据情况将t个队伍合并起来…… WA:又忘了POJ上double输出应该用%f了……so sad…

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…

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: 4748   Accepted: 2078 Description Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually exp…