【POJ 1611】【并查集】The Suspects

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水水的并查集，上学期为什么我会半天A不了，好神奇的说；

#include "iostream"using namespace std;#define Max 300010int f[Max],num[Max];//num是关键。void init();int find(int x);void join(int x,int y);int main(int argc, char const *argv[]){    int n,m,a,father,son;    while(~scanf("%d %d",&n,&m) && (n+m))    {        init();        for (int i = 0; i < m; ++i)        {            scanf("%d",&a);            scanf("%d",&father);            for (int j = 1; j < a; ++j)            {                scanf("%d",&son);                join(father,son);            }        }        printf("%d\n",num[find(0)]);//找到0所在的集合    }    return 0;}void init(){    for (int i = 0; i < n; ++i)    {        f[i]=i;        num[i]=1;    }}int find(int x){    if(x==f[x])        return x;    return f[x]=find(f[x]);}void join(int x,int y){    x=find(x);    y=find(y);    if(x!=y)    {        f[y]=x;        num[x]+=num[y];    }}

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