Problem Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following properties. There is exactly one node, called the…

题目:食物链 题意:给定一些关系.判断关系的正确性,后给出的关系服从之前的关系: 思路:难点不在并查集,在于关系的判断,尤其是子节点与根节点的关系的判断: 这个关系看似没给出,但是给出子节点与父节点的关系AND父节点与根节点的关系之后,子节点与根节点的关系是可以确定的. Rank[]存的是与父节点的关系,0是同类,1是被吃,2是吃 1.若Find(x) == Find(y) ,则x y有关系,直接判断关系: 1)  d == 1, Rank[x] == Rank[y] ,  否则fake++:…

题意: 题目给你一组单向边,当遇到输入0 0就证明这是一组边,当遇到-1 -1就要停止程序.让你判断这是不是一棵树 题解: 题目很简单,但是程序要考虑的很多 1.因为是一颗树,所以肯定不能出现环,这个可以用并查集来判断 2.边数量+1==节点数量 3.每一个点的入度不能大于1(例如边a->b,这个b点的入度就要加1) 代码: 1 #include<stdio.h> 2 #include<string.h> 3 #include<iostream> 4 #inclu…

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…

链接: http://poj.org/problem?id=1733 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=82830#problem/H 代码: #include <iostream> #include <cstring> #include <cstdio> #include <cstdlib> #include <algorithm> #include <vector…

链接: http://poj.org/problem?id=1456 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=82830#problem/G 代码: #include<iostream> #include<cstdio> #include<cmath> #include<algorithm> #include<cstring> #include<cstdlib> us…

A Bug's Life Time Limit: 10000MS Memory Limit: 65536K Total Submissions: 28651 Accepted: 9331 Description Background Professor Hopper is researching the sexual behavior of a rare species of bugs. He assumes that they feature two different genders and…

转自:http://blog.csdn.net/shahdza/article/details/7779230 [HDU]1213 How Many Tables 基础并查集★1272 小希的迷宫 基础并查集★1325&&poj1308 Is It A Tree? 基础并查集★1856 More is better 基础并查集★1102 Constructing Roads 基础最小生成树★1232 畅通工程 基础并查集★2120 Ice_cream's world I 基础并查集★212…

并查集的介绍可以看下https://www.cnblogs.com/jkzr/p/10290488.html A - Wireless Network POJ - 2236 An earthquake takes place in Southeast Asia. The ACM (Asia Cooperated Medical team) have set up a wireless network with the lap computers, but an unexpected afters…

并查集的经典题型,POJ上题目还是中文= =,一般看到中文题都会感觉不太简单,这道题的数学归纳用得比较多,可以简化代码,挺有意思的. 同类型的题目还有POJ1703,比这个要简单,想了解并查集基本介绍或想参考Code请移步:算法手记 之 数据结构(并查集详解)(POJ1703) 存在食物链: A吃B,B吃C,C吃A 给出两种判断:1 a b 指a和b相同 2 a b 指a吃b 现依照题目输入,输出判断的错误次数:1.a,b超过N错误 2.a,b不符合前面判断则错误 Code仅供参考: //食物链…