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;
}