C++ 代码

#include <iostream>
#include <unordered_map>
#include <set>
using namespace std;

unordered_map<string, set<string>> title, author, key, pub, year;

void query(unordered_map<string, set<string>> &map, string s)
{
    if (map.find(s) != map.end())
        for (auto res : map[s])
            cout << res << endl;
    else
        cout << "Not Found" << endl;
}

int main()
{
    int n;
    cin >> n;
    while (n--)
    {
        string id, _title, _author, _key, _pub, _year;
        cin >> id;
        getchar();
        getline(cin, _title), title[_title].insert(id);
        getline(cin, _author), author[_author].insert(id);
        while (cin >> _key)
        {
            key[_key].insert(id);
            if (getchar() == '\n')
                break;
        }
        getline(cin, _pub), pub[_pub].insert(id);
        cin >> _year, year[_year].insert(id);
    }
    int m;
    cin >> m;
    while (m--)
    {
        int x;
        scanf("%d: ", &x);
        string str;
        getline(cin, str);
        cout << x << ": " << str << endl;
        switch (x)
        {
            case 1: query(title, str); break;
            case 2: query(author, str); break;
            case 3: query(key, str); break;
            case 4: query(pub, str); break;
            case 5: query(year, str); break;
        }
    }
    return 0;
}