Peter's Hobby Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 545    Accepted Submission(s): 237 Problem Description Recently, Peter likes to measure the humidity of leaves. He recorded a leaf…

http://acm.hdu.edu.cn/showproblem.php? pid=4865 大致题意:有三种天气和四种叶子状态.给出两个表,各自是每种天气下叶子呈现状态的概率和今天天气对明天天气的概率. 给出n天叶子的状态.输出最有可能的天气序列. 思路:wl[i][j]表示天气为i,叶子为j的概率,ww[i][j]表示今天天气为i明天天气为j的概率,st[i]表示第一天天气为i的概率. 对于叶子序列{a1,a2......an},存在一个天气序列{b1,b2......bn},那么总的概率…

Peter's Hobby Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 292    Accepted Submission(s): 132 Problem Description Recently, Peter likes to measure the humidity of leaves. He recorded a leaf…

Peter's Hobby Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 283    Accepted Submission(s): 128 Problem Description Recently, Peter likes to measure the humidity of leaves. He recorded a leaf…

题意:已知昨天天气与今天天气状况的概率关系(wePro),和今天天气状态和叶子湿度的概率关系(lePro)第一天为sunny 概率为 0.63,cloudy 概率 0.17,rainny 概率 0.2.给定n天的叶子湿度状态,求这n天最可能的天气情况 分析:概率dp设 dp[i][j] 表示第i天天气为j的最大概率,pre[i][j]表示第i天天气最可能为j的前一天天气,dp[i][j]=max(dp[i-1][k]+log(wePro[k][j])+log(lePro[j][lePos[i]]…

题目链接 题意 : 给你两个表格,第一个表格是三种天气下出现四种湿度的可能性.第二个表格是,昨天出现的三种天气下,今天出现三种天气的可能性.然后给你这几天的湿度,告诉你第一天出现三种天气的可能性,让你求出最可能出现的天气序列 . 思路 : 定义第 i 天叶子湿度为hum[i].第 i 天,天气为 j 的最大概率为dp[i][j].wealea[i][j]表示天气为 i 叶子为j的概率,weawea[i][j]表示今天天气为 i 明天天气为j的概率,st[i]表示第一天天气为i的概率.pre[i]…

http://acm.split.hdu.edu.cn/showproblem.php?pid=4405 Aeroplane chess Problem Description   Hzz loves aeroplane chess very much. The chess map contains N+1 grids labeled from 0 to N. Hzz starts at grid 0. For each step he throws a dice(a dice have six…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5378 题意:一棵n个节点的树.对其节点进行标号(1~n).求恰好存在k个节点的标号是其节点所在子树的最大值的方案数. 解法: 首先,总共有n!中标号方案.而如果求出n个节点中出现k个上述节点的概率p.方案数等于n!* p. dp[i][j] 表示钱i个节点有j个上述节点的概率.转移较容易推出. dp[i][j] = dp[i-1][j] * (c[i]-1) / c[i] + dp[i-1][j-1…

Card Collector Problem Description In your childhood, do you crazy for collecting the beautiful cards in the snacks? They said that, for example, if you collect all the 108 people in the famous novel Water Margin, you will win an amazing award.  As a…

给出2个影响矩阵,一个是当天天气对湿度的影响,一个是前一天天气对当天天气的影响. 即在晴天(阴天.雨天)发生Dry(Dryish.Damp.Soggy)的概率,以及前一天晴天(阴天.雨天)而今天发生晴天(阴天.雨天)的概率. 其中第一天的晴天阴天雨天概率为0.63,0.17,0.20 输入n天的湿度情况,输出最有可能的n天的天气. 用dp[i][j]表示第i天为j天气的概率,用pre[i][j]表示它的前驱. 注意由于概率相乘次数过多,要用log放大..不然会接近0.精度不够.误差大 dp[i]…