poj 1611

http://poj.org/problem?id=1611

题意：0为传染源，和0在同一集合内的都认定为患者

#include<iostream>#include<cstdio>#include<algorithm>using namespace std;int father[30005],a[30005],rank[50005];int Find(int x){while(x!=father[x])x=father[x];return x;}int main(){int n,m,i,k,x,y;while(scanf("%d%d",&n,&m)&&n||m){for(i=0;i<=n;i++){father[i]=i;rank[i]=1;}while(m--){scanf("%d",&k);for(i=0;i<k;i++)scanf("%d",&a[i]);for(i=1;i<k;i++){x=Find(a[0]);y=Find(a[i]);if(x!=y){father[y]=x;rank[x]+=rank[y];}}}printf("%d\n",rank[Find(0)]);//居然因为rank[father[0]]错了好久，哎}return 0;}