E. Famil Door and Roads 题目连接: http://www.codeforces.com/contest/629/problem/E Description Famil Door's City map looks like a tree (undirected connected acyclic graph) so other people call it Treeland. There are n intersections in the city connected b…

题目链接: http://www.codeforces.com/contest/629/problem/E 题解: 树形dp. siz[x]为x这颗子树的节点个数(包括x自己) dep[x]表示x这个节点的深度,从1开始(其实从什么开始都可以,我们这里用到的只是相对距离) 对于查询u,v,总共有三种情况: 1.u为公共祖先 设x为(u,v)链上u的儿子,则我们知道新边只能从非x子树的点(n-siz[x]连到以v为根的子树上的点(siz[v]) 则新边的总条数为(n-siz[x])*siz[v]…

Famil Door's City map looks like a tree (undirected connected acyclic graph) so other people call it Treeland. There are n intersections in the city connected by n - 1 bidirectional roads. There are m friends of Famil Door living in the city. The i-t…

C. Famil Door and Brackets 题目连接: http://www.codeforces.com/contest/629/problem/C Description As Famil Door's birthday is coming, some of his friends (like Gabi) decided to buy a present for him. His friends are going to buy a string consisted of roun…

题目链接: http://codeforces.com/contest/629/problem/C 题意: 长度为n的括号,已经知道的部分的长度为m,现在其前面和后面补充‘(',或')',使得其长度为n,且每个左括号都能找到右括号与它匹配. 题解: dp[i][j]表示长度为i,平衡度为j的合法括号序列的总数,这里平衡度定义是‘('比')'多多少个,或')'比’('多多少个. #include<iostream> #include<cstring> #include<cstd…

居然补完了 组合 A - Far Relative’s Birthday Cake import java.util.*; import java.io.*; public class Main { public static void main(String[] args) { Scanner cin = new Scanner (new BufferedInputStream (System.in)); int n = cin.nextInt (); int[] col = new int[…

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…

A. Far Relative's Birthday Cake 题目连接: http://www.codeforces.com/contest/629/problem/A Description Door's family is going celebrate Famil Doors's birthday party. They love Famil Door so they are planning to make his birthday cake weird! The cake is a…

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…