1118. Birds in Forest (25)

#include <iostream>
#include <vector>
#include <algorithm>
#include <stack>
#include <map>
using namespace std;
int father[10001];
int to[10001];

int find(int x){
    while (x != father[x]) {
        x = father[x];
    }
    return x;
}
void Union(int a, int b){
    a = find(a);
    b = find(b);
    if(a < b) father[b] = a;
    else father[a] = b;
}

int main(){
    int n;
    cin >> n;
    map<int, bool> ma;
    vector<int> v;
    for (int i = 0; i < 10001; i++) {
        father[i] = i;
    }
    for (int i = 1; i <= n; i++) {
        int k;
        cin >> k;
        for (int j = 0; j < k; j++) {
            int t;
            cin >> t;
            if(!ma[t]){
                v.push_back(t);
                ma[t] = true;
                to[t] = i;//每一只鸟在那棵树上
            }
            Union(i, find(to[t]));//将两棵树联系在一起
        }
    }
    int cnt = 0;
    map<int, bool> mb;
    for (int i = 0; i < v.size(); i++) {
        if(find(to[v[i]]) && !mb[find(to[v[i]])]){
            mb[find(to[v[i]])] = true;
            cnt++;
        }
    }
    cout << cnt << ' ' << v.size() << endl;

    int k;
    cin >> k;
    for (int i = 0; i < k; i++) {
        int a, b;
        cin >> a >> b;
        if(find(to[a]) == find(to[b])){
            cout << "Yes\n";
        }else{
            cout << "No\n";
        }
    }
    return 0;
}