URL: http://cstest.scu.edu.cn/soj/problem.action?id=1824
简单的并查集问题，代码：
#include <cstdio>
#include <cstring>
int set[30010];int find_set(int x){return set[x] == x ? x : ( set[x] = find_set(set[x]) );
}void union_set(int x, int y){if( (x = find_set(x)) != (y = find_set(y)) )set[x] = y;
}int main(){int n, m, k, t, s, fa, ans;while(~scanf("%d %d", &n, &m) && (m || n)){for(int i = 0; i < n; i++)set[i] = i;while(m--){scanf("%d %d", &k, &s); k--;while(k--){scanf("%d", &t);union_set(s,t);}}fa = find_set(0); ans = 0;for(int i = 0; i < n; i++)if(find_set(i) == fa)ans++;printf("%d\n", ans);}return 0;
}