并查集并查集（Union-find Sets）是一种非常精巧而实用的数据结构，它主要用于处理一些不相交集合的合并问题。一些常见的用途有求连通子图、求最小生成树的 Kruskal 算法和求最近公共祖先（Least Common Ancestors, LCA）等。使用并查集时，首先会存在一组不相交的动态集合 S={S1,S2,⋯,Sk}，一般都会使用一个整数表示集合中的一个元素。每个集

Problem B: War点击打开题目链接      A war is beinglead between two countries, A and B. As a loyal citizen of C, you decide tohelp your country’s espionage by attending the peace-talks taking place t

Friends There is a town with N citizens. It is known that some pairsof people are friends. According to the famous saying that “The friends of myfriends are my friends, too” it follows that if A a

Wireless NetworkTime Limit: 10000MS Memory Limit: 65536KTotal Submissions: 15990 Accepted: 6750DescriptionAn earthquake takes place in Southeast Asia. The ACM (

Ubiquitous Religions点击打开题目链接Time Limit: 5000MS Memory Limit: 65536KTotal Submissions: 23669 Accepted: 11654DescriptionThere are so many different religions in t

The Suspects点击打开题目链接Time Limit: 1000MS Memory Limit: 20000KTotal Submissions: 22109 Accepted: 10746DescriptionSevere acute respiratory syndrome (SARS), an atypi

Is It A Tree?Time Limit: 1000MS Memory Limit: 10000KTotal Submissions: 21912 Accepted: 7483DescriptionA tree is a well-known data structure that is either empty