#include <cstdio> #include <iostream> #include <cstring> #include <algorithm> using namespace std; int t,n; double dp[100010]; int main() { scanf("%d",&t); int cas=1; while(t--) { scanf("%d",&n); dp[n]=0…

题目链接:LightOJ - 1248 Description Given a dice with n sides, you have to find the expected number of times you have to throw that dice to see all its faces at least once. Assume that the dice is fair, that means when you throw the dice, the probability…

题目链接: http://acm.hdu.edu.cn/contests/contest_showproblem.php?pid=1010&cid=459 找出公式,公式有实际意义,某种情形当重复做n次实验时会出现一次,即出现的概率为1/n,现在要想出现这种情形,平均要做多少次实验,显然平均要做n次. 说一个具体的,比如掷色子,有6个点,6个点随机等概率出现.掷一次色子出现1的概率为1/6,现在想掷出1来,平均要掷色子多少次,即次数的数学期望是多少. 可以证明: 设掷i次色子才出现1的概率为p[…

题意:有 t 只老虎,d只鹿,还有一个人,每天都要有两个生物碰面,1.老虎和老虎碰面,两只老虎就会同归于尽 2.老虎和人碰面或者和鹿碰面,老虎都会吃掉对方 3.人和鹿碰面,人可以选择杀或者不杀该鹿4.鹿和鹿碰面,没事问人存活下来的概率 析:最后存活肯定是老虎没了,首先可以用概率dp来解决,dp[i][j] 表示 还剩下 i 考虑, j 只鹿存活的概率是多少. 然后每次分析这几种情况即可. 还有一种思路就是只要考虑老虎没了,只要老虎没了就能存活,只要计算老虎全死完的概率就好,首先如果老虎是奇数,是…

Description Given a dice with n sides, you have to find the expected number of times you have to throw that dice to see all its faces at least once. Assume that the dice is fair, that means when you throw the dice, the probability of occurring any fa…

Dice Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 180    Accepted Submission(s): 121 Special Judge Problem Description You have a dice with m faces, each face contains a distinct number. We…

Problem Description There is a dice with n sides, which are numbered from 1,2,...,n and have the equal possibility to show up when one rolls a dice. Each side has an integer ai on it. Now here is a game that you can roll this dice once, if the i-th s…

题意:求用N(1<=N<=100)个骰子掷出M(1<=M<=600)的概率 分析:直接求概率可能出现6^100次方,会爆精度.可以用一个数组dp[i][j]记录用i个骰子掷出j的概率.i为0时无论j是多少,概率都是0.i为1时,j从1-6的概率都是1/6.其余可以递推得到 dp[i][j]  = 0 (j<i || j>6*i),sigma(dp[i-1][max(0,j-k)])  (1<=k<=6) #include<stdio.h> #in…

时间限制:10000ms 单点时限:1000ms 内存限制:256MB 描述 What is possibility of rolling N dice and the sum of the numbers equals to M? 输入 Two integers N and M. (1 ≤ N ≤ 100, 1 ≤ M ≤ 600) 输出 Output the possibility in percentage with 2 decimal places. 样例输入 2 10 样例输出 8.3…

版权声明:欢迎关注我的博客,本文为博主[炒饭君]原创文章,未经博主同意不得转载 https://blog.csdn.net/a1061747415/article/details/36685493 Dice Problem Description You have a dice with m faces, each face contains a distinct number. We assume when we tossing the dice, each face will occur r…