B. Far Relative’s Problem   time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Famil Door wants to celebrate his birthday with his friends from Far Far Away. He has n friends and each of th…

  A. Far Relative’s Birthday Cake   time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Door's family is going celebrate Famil Doors's birthday party. They love Famil Door so they are planning…

B. Far Relative's Problem 题目连接: http://www.codeforces.com/contest/629/problem/B Description Famil Door wants to celebrate his birthday with his friends from Far Far Away. He has n friends and each of them can come to the party in a specific range of…

B. Far Relative’s Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Famil Door wants to celebrate his birthday with his friends from Far Far Away. He has n friends and each of them c…

Educational Codeforces Round 40 F. Runner's Problem 题意: 给一个$ 3 * m \(的矩阵,问从\)(2,1)$ 出发 走到 \((2,m)\) 的方案数 \(mod 1e9 + 7\), 走的规则和限制如下: From the cell (i, j) you may advance to: (i - 1, j + 1) - only if i > 1, (i, j + 1), or (i + 1, j + 1) - only if i <…

Far Relative's Problem Time Limit: 2000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64u Submit Status Description Famil Door wants to celebrate his birthday with his friends from Far Far Away. He has n friends and each of them can come to…

A. Far Relative's Birthday Cake time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Door's family is going celebrate Famil Doors's birthday party. They love Famil Door so they are planning to m…

题意:n个人,在规定时间范围内,找到最多有多少对男女能一起出面. 思路:ans=max(2*min(一天中有多少个人能出面)) #include<iostream> #include<string> #include<algorithm> #include<cstdlib> #include<cstdio> #include<set> #include<map> #include<vector> #includ…

题目链接:http://codeforces.com/problemset/problem/629/E 询问这个简单环的期望.考虑将这个环拆成两部分. 令${deep[x]>=deep[y]}$,${size[x]}$表示以$x$为根的子树大小,${sdown[x]}$示以$x$为根的子树的所有节点到$x$的距离和,${sall[x]}$所有点到$x$的距离和.${ne}$表示从${y-->x}$路径上${y}$的儿子. 1.${dis(x,y)}$这是一个环肯定要经过的,算入答案. 2.分情…

A - Noldbach problem 题面链接 http://codeforces.com/contest/17/problem/A 题面 Nick is interested in prime numbers. Once he read about Goldbach problem. It states that every even integer greater than 2 can be expressed as the sum of two primes. That got Nic…