【POJ】The Suspects（裸并查集）

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn = 33333;
int fa[maxn];
int num[maxn];
int n,m,t;
void init(){
for(int i = 0; i < n; i++) {fa[i] = i; num[i] = 1;}
}
int find_father(int u){
return fa[u] == u ? u : fa[u] = find_father(fa[u]);
}
int main(){
while(scanf("%d%d",&n,&m)){
if(!m && !n) break;
init();
for(int i = 0; i < m; i++){
scanf("%d",&t);
int x,y;
for(int j = 0; j < t; j++){
scanf("%d",&y);
if(!j) x = y;
else{
int fy = find_father(y);
int fx = find_father(x);
if(fy > fx) swap(fy,fx); //为了避免麻烦。统一让小的根合并到大的根
if(fy != fx){
fa[fy] = fx;
num[fx] += num[fy];
}
}
}
}
t = find_father(0);
printf("%d\n",num[t]);
}
return 0;
}