poj1611 the suspects（并查集）

#include<cstdio>
#define N 30005
int fa
,n,m;
int find(int x){
return fa[x]==x?x:fa[x]=find(fa[x]);
}
int main(){
//  freopen("a.in","r",stdin);
while(1){
int ans=1;
scanf("%d%d",&n,&m);
if(n==0&&m==0) break;
for(int i=0;i<n;++i) fa[i]=i;
while(m--){
int k,a,b;
scanf("%d%d",&k,&a);
for(int i=1;i<k;++i){
scanf("%d",&b);
int xx=find(a),yy=find(b);
if(xx!=yy) f[yy]=xx;
}
}
for(int i=1;i<n;++i)
if(find(i)==find(0)) ans++;
printf("%d\n",ans);
}
return 0;
}