http://acm.hdu.edu.cn/showproblem.php?pid=4405 题意:在一个1×n的格子上掷色子,从0点出发,掷了多少前进几步,同时有些格点直接相连,即若a,b相连,当落到a点时直接飞向b点.求走到n或超出n期望掷色子次数 分析:简单的题目,拿来入门很不错: 如果没有飞机的线 ,这题就是直接 dp[i]+=dp[i+x]/6 +1 了 : 当前的期望由子期望相加 : 那航线怎么考虑呢?一开始我以为是加上可以走到点的dp[v] ,可是仔细推敲这是不对了,在注意到航线的…

题意:某人掷骰子,数轴上前进相应的步数,会有瞬移的情况,求从0到N所需要的期望投掷次数. 解题关键:期望dp的套路解法,一个状态可以转化为6个状态,则该状态的期望,可以由6个状态转化而来.再加上两个状态的消耗即可. #include<cstdio> #include<cstring> #include<algorithm> #include<cstdlib> #include<cmath> #include<iostream> usi…

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 faces with equal probability to face up and the number…

题意:你从0开始,要跳到 n 这个位置,如果当前位置是一个飞行点,那么可以跳过去,要不然就只能掷骰子,问你要掷的次数数学期望,到达或者超过n. 析:概率DP,dp[i] 表示从 i  这个位置到达 n 要掷的次数的数学期望.然后每次掷的数就是1-6,概率都相等为1/6,再特殊标记一下飞行点,那么就容易写过了. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #in…

题意 抄袭自https://www.cnblogs.com/Paul-Guderian/p/7624039.html 正在玩飞行棋.输入n,m表示飞行棋有n个格子,有m个飞行点,然后输入m对u,v表示u点可以直接飞向v点,即u为飞行点.如果格子不是飞行点,扔骰子(1~6等概率)前进.否则直接飞到目标点.每个格子是唯一的飞行起点,但不是唯一的飞行终点.问到达或越过终点的扔骰子期望数. 从0出发!! Sol 比较zz的期望dp 设$f[i]$表示从$i$出发,到达$n$的期望步数 转移的时候讨论一下…

http://acm.hdu.edu.cn/showproblem.php?pid=4405 明显,有飞机的时候不需要考虑骰子,一定是乘飞机更优 设E[i]为分数为i时还需要走的步数期望,j为某个可能投出的点数如果从i向i-j推导,我们并不能确定i的转移方向,因为可能有两个i-j有飞机其目的地是i,所以我们选择从i向i+j推导期望 如果设G[i]为分数为i时已经走过的步数期望,那么要确定G[i+j]需要知道P(i|i+j),也即转移到i+j的条件下从i转移来的概率,比较麻烦 由题意,设match…

题目 http://kicd.blog.163.com/blog/static/126961911200910168335852/ 根据里面的例子,就可以很简单的写出来了,虽然我现在还是不是很理解为什么“是下一分钟,故要加上1.”? 好吧,先写着,有事没事想一想,也许时间长了就明白了. 别的人解释很棒:(虽然我还没全懂) //e[i]表示i的位置走到n所需要的期望步数//那么e[i]怎么求,首先e[i]走到e[i+1]的概率为1/6 ,//而e[i+1]是走到终点的期望步数,所以e[i]=e[i…

Aeroplane chess Time Limit: 1 Sec  Memory Limit: 32 MB[Submit][Stataus][Discuss] 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 s…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1597    Accepted Submission(s): 1088 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids lab…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1581    Accepted Submission(s): 1082 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids la…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=4405 Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)Memory Limit: 32768/32768 K (Java/Others) 问题描述 Hzz loves aeroplane chess very much. The chess map contains N+1 grids labeled from 0 to N. Hzz s…

http://acm.hdu.edu.cn/showproblem.php?pid=4405 看了一下这个博客http://kicd.blog.163.com/blog/static/126961911200910168335852/ Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1336    Acce…

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 faces with equal probability to face up and the numbers on the faces are 1,2,3,4,5,6). Whe…

题目大意:一个跳棋游戏,每置一次骰子前进相应的步数.但是有的点可以不用置骰子直接前进,求置骰子次数的平均值. 题目分析:状态很容易定义:dp(i)表示在第 i 个点出发需要置骰子的次数平均值.则状态转移方程为: dp(i)=singma(pk*dp(i+k))+1 (如果在 i 处必须置骰子才能前进) dp(i)=dp(s) (如果在 i 处能直接到达s处) 代码如下: # include<iostream> # include<cstdio> # include<vecto…

http://acm.hdu.edu.cn/showproblem.php?pid=4405   题意:问从起点到终点需要步数的期望,1/6的概率走1.2.3.4.5.6步.有的点a有路可以直接到b,满足a<b. 期望dp,水题,总感觉以前做过类似的,可能因为期望dp基础题都是这个德行. 代码 #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #inclu…

传送门 期望dp简单题啊. 不过感觉题意不太对. 手过了一遍样例发现如果有捷径必须走. 这样的话就简单了啊. 设f[i]" role="presentation" style="position: relative;">f[i]f[i]表示从第i个格子出发到第n个格子的期望步数. 显然就可以从f[i+1]~f[i+6]转移过来了,注意如果f下标超过n期望步数都是0. 代码: #include<bits/stdc++.h> #define…

//从0到n有n+1个格子 //对于格子i,掷一次骰子的数为x.那么能够从位置i到位置i+x //格子之间有连线,假设格子a和b有连线,那么从a到b不用掷骰子 //求从0到n的骰子掷的次数的期望 //dp[i] = 1/6*segma(dp[k]) + 1 (i<=k<=i+6) #include<cstdio> #include<iostream> #include<cstring> using namespace std ; const int maxn…

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…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1503    Accepted Submission(s): 1025 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids la…

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 faces with equal probability to face up and the numbers on the faces are 1,2,3,4,5,6). Whe…

Problem Description Hzz loves aeroplane chess very much. The chess map contains N+ grids labeled to N. Hzz starts at grid . For each step he throws a dice(a dice have six faces with equal probability to face up and the numbers on the faces are ,,,,,)…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1667    Accepted Submission(s): 1123 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids lab…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1122    Accepted Submission(s): 762 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids lab…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4239    Accepted Submission(s): 2674 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids lab…

Aeroplane chess Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1628    Accepted Submission(s): 1103 Problem Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids la…

题目: 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 faces with equal probability to face up and the numbers on the fac…

专题链接 第一题--poj3744 Scout YYF I  链接 (简单题) 算是递推题 如果直接推的话 会TLE 会发现 在两个长距离陷阱中间 很长一部分都是重复的 我用 a表示到达i-2步的概率 b表示到达i-1步的概率 c表示到达i步的概率 如果数很大的话 中间肯定会有重复的a,b,c 直接将i挪到最近的陷阱前一位 i = a[o]-1,大大节省时间. #include <iostream> #include<cstdio> #include<cstring>…

概率类题目一直比较弱,准备把kuangbin大师傅总结的这篇题刷一下! 我把下面的代码换成了自己的代码! 原文地址:http://www.cnblogs.com/kuangbin/archive/2012/10/02/2710606.html *************************************************************** 概率DP主要用于求解期望.概率等题目. 转移方程有时候比较灵活. 一般求概率是正推,求期望是逆推.通过题目可以体会到这点. 首先…

概率DP/数学期望 kuangbin总结中的第4题 啊还是求期望嘛……(话说Aeroplane chess这个翻译怎么有种chinglish的赶脚……) 好像有点感觉了…… 首先不考虑直飞的情况: f[i]表示从第 i 格到end的期望掷骰子次数,那明显就是从f[i+1]~f[i+6]各1/6的概率(系数) 转移过来啦~ 那直飞呢? so easy,f[i]=f[fly[i]]即可,其中fly[i]表示从第 i 格飞到的格子.当然直飞就不用再考虑1/6的掷骰子情况了…… 从n-1往0逆推即可 P…

概率dp特征: 概率DP一般求的是实际结果,在DP过程中,当前状态是由所有子状态的概率共同转移而来,所以概率DP只是利用了DP的动态而没有规划(即只需转移无需决策).-------qkoqhh A - Collecting Bugs 题意:一个软件有s个子系统,会产生n种bug.某人一天发现一个bug,这个bug属于某种bug,发生在某个子系统中. 求找到所有的n种bug,且每个子系统都找到bug,这样所要的天数的期望.需要注意的是:bug的数量是无穷大的,所以发现一个bug,出现在某个子系统的…