Lang:G++
Edit12345678910111213141516171819202122232425262728293031#include <bits/stdc++.h>using namespace std;using psd = pair<string, double>;int main(void) {ios::sync_with_stdio(false);set<psd> vis;int N;cin >> N;for (int i = 0; i < N; ++ i) {int M;cin >> M;set<psd> tmp;for (int j = 0; j < M; ++ j) {string id, date;double price;cin >> id >> date >> price;tmp.insert(psd(id, price));}if (i == 0) vis = tmp;else {for (auto &p: vis) if (tmp.find(p) == end(tmp)) vis.erase(p);}}for (auto &p: vis) cout << p.first << endl;return 0;}