一开始以为两道题是一样的,POJ的过了直接用相同代码把HDU的交了,结果就悲剧了.最后发现HDU的没有考虑入度不能大于一. 题意:用树的定义来 判断吧,无环,n个结点最多有n-1条边,不然就会有环.只有一个入度为0的结点,不存在入度大于1的结点. 思路:并查集. AC代码: #include<stdio.h> #include<string.h> #define N 100005 int in[N],pre[N],a,b,c[N]; void init()//初始化 { for(i…

  HDU 1272 I - 小希的迷宫 Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u Submit Status Practice HDU 1272 Appoint description: Description 上次Gardon的迷宫城堡小希玩了很久(见Problem B),现在她也想设计一个迷宫让Gardon来走.但是她设计迷宫的思路不一样,首先她认为所有的通道都应该是双向连通的,…

http://acm.hdu.edu.cn/showproblem.php?pid=1829 http://poj.org/problem?id=2492 臭虫有两种性别,并且只有异性相吸,给定n条臭虫(编号1-n)和m对关系,判断是否是出现同性恋的情况. 这题跟食物链的题类似,这里只有两种关系,关系是同性或者异性. 对于每只动物创建两个元素  同性或异性,并用这 2×n个元素建立并查集. 首先判断输入的x和y是否是一个组的.是就flag=1. 然后,如果x和y是一对,那么合并x和y+n,x+n…

Find them, Catch them Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 43132   Accepted: 13257 Description The police office in Tadu City decides to say ends to the chaos, as launch actions to root up the TWO gangs in the city, Gang Drago…

Wireless Network Time Limit: 10000MS   Memory Limit: 65536K Total Submissions: 25022   Accepted: 10399 Description An earthquake takes place in Southeast Asia. The ACM (Asia Cooperated Medical team) have set up a wireless network with the lap compute…

食物链 Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 66294   Accepted: 19539 Description 动物王国中有三类动物A,B,C,这三类动物的食物链构成了有趣的环形.A吃B, B吃C,C吃A. 现有N个动物,以1-N编号.每个动物都是A,B,C中的一种,但是我们并不知道它到底是哪一种. 有人用两种说法对这N个动物所构成的食物链关系进行描述: 第一种说法是"1 X Y",表示X和Y是同…

The Suspects Time Limit: 1000MS   Memory Limit: 20000K Total Submissions: 35206   Accepted: 17097 Description Severe acute respiratory syndrome (SARS), an atypical pneumonia of unknown aetiology, was recognized as a global threat in mid-March 2003. T…

题意: 一次地震震坏了所有网点 现在开始修复它们 有N个点 距离为d的网点可以进行通信 O p   代表p点已经修复 S p q 代表询问p q之间是否能够通信 思路: 基础并查集 每次修复一个点重新刷一边图就行了 /* *********************************************** Author :Sun Yuefeng Created Time :2016/11/1 15:40:35 File Name :food.cpp ******************…

Background Professor Hopper is researching the sexual behavior of a rare species of bugs. He assumes that they feature two different genders and that they only interact with bugs of the opposite gender. In his experiment, individual bugs and their in…

1.POJ 1733 Parity game Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5744   Accepted: 2233 Description Now and then you play the following game with your friend. Your friend writes down a sequence consisting of zeroes and ones. You cho…