B - Card Time Limit:5000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u Submit Status Description There are x cards on the desk, they are numbered from 1 to x. The score of the card which is numbered i(1<=i<=x) is i. Every round Bi…

Card Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 191    Accepted Submission(s): 52Special Judge Problem Description There are x cards on the desk, they are numbered from 1 to x. The score o…

Problem Description There are x cards on the desk, they are numbered from 1 to x. The score of the card which is numbered i(1<=i<=x) is i. Every round BieBie picks one card out of the x cards,then puts it back. He does the same operation for b round…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4336 题意: 一共有n种卡片.每买一袋零食,有可能赠送一张卡片,也可能没有. 每一种卡片赠送的概率为p[i],问你将n种卡片收集全,要买零食袋数的期望. 题解: 表示状态: dp[state] = expectation state表示哪些卡片已经有了 找出答案: ans = dp[0] 什么都没有时的期望袋数 如何转移: 两种情况,要么得到了一张新的卡片,要么得到了一张已经有的卡片或者啥都没有.…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5159 题解: 考虑没一个数的贡献,一个数一次都不出现的次数是(x-1)^b,而总的排列次数是x^b,所以每一个数有贡献的次数都是x^b-(x-1)^b,所以最后推导的公式就是: (x^b-(x-1)^b)*(1+2+...+x)/(x^b)=(1-((x-1)/x)^b)*(1+x)*x/2 代码: #include<iostream> #include<cstdio> #inclu…

题目地址: http://acm.hdu.edu.cn/showproblem.php?pid=4336 题意简单,直接用容斥原理即可 AC代码: #include <iostream> #include <cstdio> #include <cstring> #include <string> #include <cstdlib> #include <cmath> #include <vector> #include &…

D - Joyful Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Description Sakura has a very magical tool to paint walls. One day, kAc asked Sakura to paint a wall that looks like an $M \times N$ matrix. The wal…

题目链接 495. Kids and Prizes Time limit per test: 0.25 second(s)Memory limit: 262144 kilobytes input: standardoutput: standard ICPC (International Cardboard Producing Company) is in the business of producing cardboard boxes. Recently the company organiz…

LOOPS Time Limit: 15000/5000 MS (Java/Others)    Memory Limit: 125536/65536 K (Java/Others) Total Submission(s): 1864    Accepted Submission(s): 732 Problem Description Akemi Homura is a Mahou Shoujo (Puella Magi/Magical Girl). Homura wants to help h…

Collecting Bugs Time Limit: 10000MS   Memory Limit: 64000K Total Submissions: 3523   Accepted: 1740 Case Time Limit: 2000MS   Special Judge Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material s…