L2-049 鱼与熊掌
https://pintia.cn/problem-sets/994805046380707840/exam/problems/1781658570803388424?type=7&page=1

#include <bits/stdc++.h>
using namespace std;
int main(){
    int n,m;
    cin>>n>>m;
    vector<vector<int>> ve(n);
    for(int i=0;i<n;i++){
        int k;
        cin>>k;

        for(int j=0;j<k;j++) {
            int a;
            cin>>a;
            ve[i].push_back(a);
        }
    }
    int num;
    cin>>num;
    for(int i=0;i<num;i++){
        int c,d;
        int count=0;
        cin>>c>>d;
        for(int j=0;j<n;j++){
        if(find(ve[j].begin(),ve[j].end(),c)!=ve[j].end()&&find(ve[j].begin(),ve[j].end(),d)!=ve[j].end()){
            count++;

        }
    }
        cout<<count<<endl;
    }
    return 0;
}