#include <iostream>
#include <vector>
#include <unordered_map>
#include <algorithm>
using namespace std;
const int N = 4E4 + 10;
unordered_map<string, int> mp;   //  建立索引
vector<vector<int>> course(N);   //  学生的课表
int id = 0;
int main(){
    int n, k;
    cin >> n >> k;
    int cno, num;
    string name;
    while(k -- ){
        cin >> cno >> num;
        while(num -- ){
            cin >> name;
            if(mp.find(name) == mp.end())   mp[name] = id ++ ;
            course[mp[name]].push_back(cno);
        }
    }
    while(n -- ){
        cin >> name;
        cout << name << " ";
        if(mp.find(name) == mp.end())   cout << "0" << endl;
        else{
            int sno = mp[name];
            cout << course[sno].size() << " ";
            sort(course[sno].begin(), course[sno].end());
            for(int i = 0; i < course[sno].size(); i ++ ){
                cout << course[sno][i];
                if(i == course[sno].size() - 1) cout << endl;
                else    cout << " "; 
            }
        }
    }
    return 0;
}

其实可以直接

unordered_map<string, <vector<int>>