Domination Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3822 Description Edward is the headmaster of Marjar University. He is enthusiastic about chess and often plays chess with his friends.…

题目链接 参考博客:http://blog.csdn.net/napoleon_acm/article/details/40020297 题意:给定n*m的空棋盘 每一次在上面选择一个空的位置放置一枚棋子,直至每一行每一列都至少有一个棋子,求放置次数的期望 分析: dp[i][j][k] 表示当前用了<=k个chess ,覆盖了i行j列(i*j的格子 每行至少一个,每列至少一个)的概率. dp[i][j][k] 由 dp[i][j][k-1] , dp[i-1][j][k-1], dp[i][j…

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…

一个n行m列的棋盘,每天可以放一个棋子,问要使得棋盘的每行每列都至少有一个棋子 需要的放棋子天数的期望. dp[i][j][k]表示用了k天棋子共能占领棋盘的i行j列的概率. 他的放置策略是,每放一次,就会有四种可能 1)增加一行一列 2)增加一行 3)增加一列 4)不变 所以他放置的概率就可以求出来,每次放下的概率就是当前能放的点除以总的空的点数. 最后统计期望的时候需要统计在第k天刚好符合占满n行m列的概率,就是dp[i][j][k]-dp[i][j][k-1] #include <cstd…

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…

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 a chess piec…

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…

题目链接:problemId=5376">http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=5376 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 ch…

题目链接:zoj 3822 Domination 题目大意:给定一个N∗M的棋盘,每次任选一个位置放置一枚棋子,直到每行每列上都至少有一枚棋子,问放置棋子个数的期望. 解题思路:大白书上概率那一张有一道类似的题目,可是由于时间比較久了,还是略微想了一下. dp[i][j][k]表示i行j列上均有至少一枚棋子,而且消耗k步的概率(k≤i∗j),由于放置在i+1~n上等价与放在i+1行上,同理列也是如此.所以有转移方程: dp[i][j][k+1]+=dp[i][j][k]∗(n−k)(S−k) d…

ZOJ Problem Set - 3822 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 lar…