题解 | 生词篇章查询

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

int main() {
    int n, m, len;
    cin >> n;
    string word;
    unordered_map<string, set<int>> dict;

    for (int i = 1; i <= n; ++i) {
        cin >> len;
        while (len--) {
            cin >> word;
            dict[word].insert(i);
        }
    }

    cin >> m;

    while (m--) {
        cin >> word;
        if (dict.count(word)) {
            auto it = dict[word].begin();
            while (it != dict[word].end()) {
                cout << *it << " ";
                ++it;
            }
        }
        cout << endl;
    }

    return 0;
}