题目链接 : http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=27050 ------------------------------------------------------------------------------------------------------------ 我们先考虑这个问题 有一堆牌 其中$n$张牌抽到后不放回 另$m$张牌抽到后放回 求每张牌都抽到过至少一次 需要的抽牌次数的期望 对于这…

题目传送门 题意:n根木棍,每根木棍都有一个权值,木棍有可识别的木棍和不可识别的木棍,每次抽取木棍时,会累加权值,如果是可识别的木棍就不放回,不可识别的木棍就放回,问每根木棍至少被抽取一次,权值的期望是多少. 思路:论文题? 1类棍子只会拿起一次,ans+=权值 2类棍子会拿起多次,ans+=权值*h[n]       h[n]为调和级数第n项 证明的博客 #include<bits/stdc++.h> #define rep(i,a,b) for(int i=a;i<=b;i++) #…

题目链接 题意: 地上有n种棍子, 其中有两种类型, 一种类型是可识别, 一种类型是不可识别, 每个棍子都有一个权值. 当你捡到可识别的, 那么你以后就不会再捡这个棍子, 如果是不可识别的, 那么你有可能还会捡. 问将所有棍子收集完的权值的期望. 思路: 此题借鉴参考了此篇文章:Aladdin and the Magical Sticks 首先, 这个题初看起来, 和LightOj 1027  A Dangerous Maze有点像, 只不过, 这里是要将所有的门都走遍. 先引入一个经典的问题:…

Bisharp and Charizard Time Limit: 1 Sec  Memory Limit: 256 MB Description Dragon is watching NBA. He loves James and Miami Heat. Here's an introduction of basketball game:http://en.wikipedia.org/wiki/Basketball. However the game in Dragon's version i…

找每个数的约数(暴力就够了...1~x^0.5)....看这约数的倍数最后是哪个数...若距离大于了y..统计++...然后将这个约数的最后倍数赋值为当前位置...好叼的想法题.... Program: #include<iostream> #include<stack> #include<queue> #include<stdio.h> #include<algorithm> #include<string.h> #include&…

http://acm.hdu.edu.cn/showproblem.php?pid=5806 题意:给你一个n元素序列,求第k大的数大于等于m的子序列的个数. 题解:题目要求很奇怪,很多头绪但写不出,选择跳过的题,简称想法题. 首先考虑区间的更新方法:区间左端l不动,右端r滑动, 滑到有k个数>=m时,此区间符合条件,并且发现右端点再往右滑到底,此条件一直符合(因为若加入的数小于“第K大的数”,则毫无影响.若不然,加入该数会产生一个新的第k大数,保证>=“第K大的数”>=m) 所以一找…

http://lightoj.com/volume_showproblem.php?problem=1341 Aladdin and the Flying Carpet Time Limit:3000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1341 Description It's said that Aladdin had to solve seven…

Aladdin and the Return Journey Time Limit: 2000ms Memory Limit: 32768KB This problem will be judged on LightOJ. Original ID: 134864-bit integer IO format: %lld      Java class name: Main Finally the Great Magical Lamp was in Aladdin's hand. Now he wa…

Finally the Great Magical Lamp was in Aladdin's hand. Now he wanted to return home. But he didn't want to take any help from the Genie because he thought that it might be another adventure for him. All he remembered was the paths he had taken to reac…

It's said that Aladdin had to solve seven mysteries before getting the Magical Lamp which summons a powerful Genie. Here we are concerned about the fourth mystery. In the cave, Aladdin was moving forward after passing the pathway of magical stones. H…