http://poj.org/problem?id=2096 题意:s个系统n种bug,每天找出一个bug,种类的概率是1/n,系统的概率是1/s.问:每个系统至少找出一个bug:每种类的bug都被找出.的期望天数(0<n, s<=1000) #include <cstdio> using namespace std; double d[1005][1005]; int n, s; double D; int main() { scanf("%d%d", &am…

题目 传送门:QWQ 分析 数学期望 用$ dp[i][j] $表示发现了在$ j $个子系统里面发现了$ i $个bug到$ s $个子系统里面发现了$ n $个bug需要的期望天数. $ dp[0][0] $就是答案. 然后分类一下,可以转移到$ dp[i][j] $无非就是$ dp[i+1][j+1] $ $ dp[i][j+1] $ $ dp[i+1][j] $ $ dp[i][j] $ 各自分别算一下概率,比如从$ dp[i][j] $转移过来的话概率是$ \frac{i}{n} \t…

题目链接: http://poj.org/problem?id=2096 Collecting Bugs Time Limit: 10000MSMemory Limit: 64000K 问题描述 Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets a new…

Description Georgia and Bob decide to play a self-invented game. They draw a row of grids on paper, number the grids from left to right by 1, 2, 3, ..., and place N chessmen on different grids, as shown in the following figure for example: Georgia an…

Description 有两堆石子,数量任意,可以不同.游戏开始由两个人轮流取石子.游戏规定,每次有两种不同的取法,一是可以在任意的一堆中取走任意多的石子:二是可以在两堆中同时取走相同数量的石子.最后把石子全部取完者为胜者.现在给出初始的两堆石子的数目,如果轮到你先取,假设双方都采取最好的策略,问最后你是胜者还是败者. Input 输入包含若干行,表示若干种石子的初始情况,其中每一行包含两个非负整数a和b,表示两堆石子的数目,a和b都不大于1,000,000,000. Output 输出对应也有…

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…

Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets a new program, he classifies all possible bugs into n categories. Each day he discovers exactly one bug…

Collecting Bugs Time Limit: 10000MS   Memory Limit: 64000K Total Submissions: 1716   Accepted: 783 Case Time Limit: 2000MS   Special Judge Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material st…

Collecting Bugs Time Limit: 10000MS   Memory Limit: 64000K Total Submissions: 2745   Accepted: 1345 Case Time Limit: 2000MS   Special Judge Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material s…

C - Collecting Bugs Time Limit:10000MS     Memory Limit:64000KB     64bit IO Format:%I64d & %I64u Submit Status Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software b…