foo.cc: In function ‘int main()’:
foo.cc:18:30: warning: comparison of integer expressions of different signedness: ‘std::priority_queue<long long int>::size_type’ {aka ‘long unsigned int’} and ‘long long int’ [-Wsign-compare]
   18 |                 if (pq.size()>=k&&!ok) ok=1,maxx=pq.top(),q.pop_back();
      |                     ~~~~~~~~~^~~
foo.cc:21:24: warning: comparison of integer expressions of different signedness: ‘std::priority_queue<long long int>::size_type’ {aka ‘long unsigned int’} and ‘long long int’ [-Wsign-compare]
   21 |         while(pq.size()!=k) pq.pop();
      |               ~~~~~~~~~^~~