题意:
有n个人,编号0-n-1,给出m个集合,问一共有多少个人和0号在一个集合。
思路:
直接并查集即可
// Decline is inevitable,
// Romance will last forever.
// POJ1611
//#include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <cstring>
#include <string>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <deque>
#include <vector>
using namespace std;
#define mst(a, x) memset(a, x, sizeof(a))
#define INF 0x3f3f3f3f
#define mp make_pair
#define pii pair<int,int>
#define fi first
#define se second
#define ll long long
//#define int long long
const int maxn = 3e4 + 10;
const int maxm = 25;
const int P = 1e9 + 7;
int fa[maxn];
int n, m;
int find(int x) {
if(x == fa[x]) return x;
return fa[x] = find(fa[x]);
}
void merge(int x, int y) {
x = find(x);
y = find(y);
if(x != y)
fa[x] = y;
}
void solve() {
while(scanf("%d%d", &n, &m) && (n || m)) {
for(int i = 0; i <= n; i++)
fa[i] = i;
for(int i = 1; i <= m; i++) {
int k, x;
scanf("%d%d", &k, &x);
k--;
while(k--) {
int y;
scanf("%d", &y);
merge(x, y);
}
}
int a = find(0);
int cnt = 0;
for(int i = 0; i < n; i++)
if(find(i) == a) cnt++;
printf("%d\n", cnt);
}
}
signed main() {
// ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
// int T; scanf("%d", &T); while(T--)
// int T; cin >> T; while(T--)
solve();
return 0;
}