题意:有k对队伍,每对队伍之间将举行两次比赛,两支队伍各主办一次.住宿的地方要求在两支队伍家乡的最短路的结点上或者在两支队伍的家乡.问在选择住宿处最少的情况下,怎么组成这k对队伍? 分析: 1.因为n个点,n-1条边,且连通图,因此所有队伍的关系形成一棵树. 2.树上任意两点之间的最短路是唯一的. 3.因此住宿处一定只有一个,它是k对队伍到彼此家乡的必经结点. 4.从某点出发,找一个子树中家乡的个数>=k的点作为住宿处,则以该点子树中的家乡为家乡的k支队伍,与其他k支队伍配对即可. #pragm…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output The country Treeland consists of n cities connected with n - 1 bidirectional roads in such a way that it's possible to reach every city starting…

C. Tennis Championship 题目链接 http://codeforces.com/contest/735/problem/C 题面 Famous Brazil city Rio de Janeiro holds a tennis tournament and Ostap Bender doesn't want to miss this event. There will be n players participating, and the tournament will fo…

题目链接:http://codeforces.com/problemset/problem/752/C time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Santa Claus has Robot which lives on the infinite grid and can move along its lines. He…

E. Santa Claus and Tangerines time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Santa Claus has n tangerines, and the i-th of them consists of exactly ai slices. Santa Claus came to a school…

C. Tennis Championship time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Famous Brazil city Rio de Janeiro holds a tennis tournament and Ostap Bender doesn't want to miss this event. There w…

C. Tennis Championship time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Famous Brazil city Rio de Janeiro holds a tennis tournament and Ostap Bender doesn't want to miss this event. There w…

题面: 传送门 B. Santa Claus and Keyboard Check Input file: standard input Output file: standard output Time limit: 2 second Memory limit: 256 megabytes   Santa Claus decided to disassemble his keyboard to clean it. After he returned all the keys back, he su…

雅礼集训期间我好像考完试就开始划水了啊 给出k个长度相同的字符串,每个串有一个权值,选出一些串连成一个回文串.使得选中的串的总权值最大. 如果选一个串,必须同时选一个对称的串.还有一个特殊情况是可以在最中间放一个回文的串,求一下这种情况带来的额外的收入即可. 卡自然溢出hash....需要树同构那种奇奇怪怪的hash... #include <cstdio> #include <string> #include <iostream> #include <algor…

题意:给定一个机器人的行走路线,求最少的点能使得机器人可以走这样的路线. 析:每次行走,记录一个方向向量,每次只有是相反方向时,才会增加一个点,最后再加上最后一个点即可. 代码如下: #pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #include <cmath> #…