You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all doors. If you choose the ith door, it can either take you back to the same position where you begun…

题目链接:https://vjudge.net/problem/LightOJ-1027 1027 - A Dangerous Maze    PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The p…

题目大概说你正在起点,面前有$n$个门,每个门有一个数字$x$,正数表示开这个门$x$分钟后会出去,负数表示开这个门$-x$分钟后会回到起点.选择门的概率是一样的且每次选择互不影响.问出去的时间期望是多少. $d[0]$表示从起点出发出去的期望,$d[i](1\leqslant i\leqslant n)$表示选择第i个门出去的期望: 不妨设$1\dots j$的门是正数,$j+1\dots n$的门是负数,那么: $$d[i]=x[i](1\leqslant i\leqslant j)$$ $…

你在迷宫中;开始时在你面前看到n扇门.你可以选择你喜欢的任何门.所有门的选择门的概率是相等的. 如果您选择第i个门,它可以让您回到您在xi(xi小于0)分钟内开始的相同位置,也可以在xi(xi大于0)分钟后将您带出迷宫 第一行输入t,代表t个样例,第二行输入一个n,代表这个样例有多少扇门,第三行输入n个数字,如果是正数,那么在经过xi的时间后 你可以离开迷宫,如果xi是负数,那么在|xi|的时间后你又会会到原点,问你离开迷宫的期望是多少. 假设我们离开迷宫的期望是E,如果我们选择xi为正数的门,…

1027 - A Dangerous Maze PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all…

题目链接:https://vjudge.net/problem/LightOJ-1395 1395 - A Dangerous Maze (II)    PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like.…

A - A Dangerous Maze Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Description You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal…

A Dangerous Maze You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all doors. If you choose the ith door, it can either take you back to the same positio…

A Dangerous Maze (II) LightOJ - 1395(概率dp) 这题是Light Oj 1027的加强版,1027那道是无记忆的. 题意: 有n扇门,每次你可以选择其中一扇.xi为负值的门带你abs(xi)后又回到原点.xi为正值 的门则带你离开迷宫,并且你会记住你前面选择的K道门,在下次选择的时候不会选择这些门.选择每扇门的概率相等.求走出迷宫的时间期望值. 题解: \(定义E[i] 表示记住了K道门后,显然这K道门都是为负值的门,走出迷宫的时间期望值,sum1表示为正的…

http://www.lightoj.com/volume_showproblem.php?problem=1027 You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all doors. If you choose the ith door, it ca…