Permutation Bo 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5753 Description There are two sequences h1∼hn and c1∼cn. h1∼hn is a permutation of 1∼n. particularly, h0=hn+1=0. We define the expression [condition] is 1 when condition is True,is 0 whe…

Permutation Bo 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5753 Description There are two sequences h1∼hn and c1∼cn. h1∼hn is a permutation of 1∼n. particularly, h0=hn+1=0. We define the expression [condition] is 1 when condition is True,is 0 whe…

这里是一个比较简单的问题:考虑每个数对和的贡献.先考虑数列两端的值,两端的摆放的值总计有2种,比如左端:0,大,小:0,小,大:有1/2的贡献度.右端同理. 中间的书总计有6种可能.小,中,大.其中有两种对答案有贡献,即1/3的贡献度.加和计算可得到答案. Permutation Bo Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s):…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5753 题目大意: 两个序列h和c,h为1~n的乱序.h[0]=h[n+1]=0,[A]表示A为真则为1,假为0. 函数f(h)=(i=1~n)∑ci[hi>hi−1 && hi>hi+1] 现在给定c的值,求f(h)的期望. 题目思路: [数学] 头尾的概率为1/2,中间的概率为1/3,直接求和. // //by coolxxx // #include<iostream&g…

题目链接: Permutation Bo Time Limit: 2000/1000 MS (Java/Others)     Memory Limit: 131072/131072 K (Java/Others) Problem Description There are two sequences h1∼hn and c1∼cn. h1∼hn is a permutation of 1∼n. particularly, h0=hn+1=0. We define the expression …

Permutation Bo Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 574    Accepted Submission(s): 346Special Judge Problem Description . We define the expression [condition] is 1 when condition is…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5761 题目大意: 船在(0,a),船速v1,水速v2沿x轴正向,船头始终指向(0,0),问到达(0,0)用时,无解输出Infinity. 题目思路: [数学] 说是数学其实更像物理. 很明显v1<=v2时无解. 这道题列积分方程然后解出来式子是t=a*v1/(v12-v22). 我列积分方程的时候少了一个式子没解出来. 可以看看半根毛线的.http://images2015.cnblogs.com…

当在两端时:共有n * (n - 1)种组合,满足条件的有,计算可得, counter = n * (n - 1) / 2. 其他位置时:共有n * (n - 1) * (n - 2) 种组合,满足条件的有,利用平方和公式计算可得counter = n * (n - 1) * (n - 2)  / 3. #include<bits/stdc++.h> using namespace std; int main() { int n; while(~scanf("%d",&am…

Sqrt Bo 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5752 Description Let's define the function f(n)=⌊n−−√⌋. Bo wanted to know the minimum number y which satisfies fy(n)=1. note:f1(n)=f(n),fy(n)=f(fy−1(n)) It is a pity that Bo can only use 1 unit…

Teacher Bo 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5762 Description Teacher BoBo is a geography teacher in the school.One day in his class,he marked N points in the map,the i-th point is at (Xi,Yi).He wonders,whether there is a tetrad (A,B,C,…