PKU 1611 并查集

http://acm.pku.edu.cn/JudgeOnline/problem?id=1611 题目

详细代码如下:思路很清晰.

#include <iostream>using namespace std;int parent[30005];//保存人编号的父亲int Find(int i){if (i!=parent[i])parent[i]=Find(parent[i]);return parent[i];}void Union(int i,int j){parent[j]=i;}int main (){int n,m,k,i,j,count,a,b;while (cin>>n>>m){if (n==0 && m==0)break;for (i=0;i<n;i++)//初始化父亲parent[i]=i;count=0;//for (i=1;i<=m;i++){cin>>k;cin>>a;a=Find(a);for (j=2;j<=k;j++){cin>>b;b=Find(b);if (a!=b){Union(a,b);}}}int res=Find(0);//找出有0这个人的父亲for (i=0;i<n;i++){if (res==Find(i))count++;}cout<<count<<endl;}return 0;}