trade.cpp: In function 'int main()':
trade.cpp:30:21: warning: comparison of integer expressions of different signedness: 'std::set<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
30 | if (stuff.size() > k){
| ~~~~~~~~~~~~~^~~
trade.cpp:36:20: warning: comparison of integer expressions of different signedness: 'std::set<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
36 | if (stuff.size()==k) ans = max(ans, sum-cost);
| ~~~~~~~~~~~~^~~
trade.cpp:52:21: warning: comparison of integer expressions of different signedness: 'std::set<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
52 | if (stuff.size() > k){
| ~~~~~~~~~~~~~^~~
trade.cpp:58:20: warning: comparison of integer expressions of different signedness: 'std::set<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
58 | if (stuff.size()==k && (sum-cost) == ans){
| ~~~~~~~~~~~~^~~