tickets.cpp: In function 'long long int find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:10:123: error: template argument 3 is invalid
10 | priority_queue<pair<long long, long long>, vector<pair<long long, long long> >, greater<pair<long long, long long> > pq;
| ^~
tickets.cpp:13:7: error: 'pq' was not declared in this scope
13 | pq.push({x[i][0] + x[i][m - 1], i});
| ^~
tickets.cpp:17:16: error: 'pq' was not declared in this scope
17 | sum -= pq.top().first;
| ^~
tickets.cpp:19:17: error: 'pq' was not declared in this scope
19 | }else ans[pq.top().second][m - 1] = 0;
| ^~
tickets.cpp:7:49: warning: control reaches end of non-void function [-Wreturn-type]
7 | vector<vector<int> > ans(n, vector<int>(m, -1));
| ^