foo.cc: In function ‘void solve_1020(std::vector<std::vector<int> >)’:
foo.cc:40:5: error: ‘sort’ was not declared in this scope; did you mean ‘short’?
   40 |     sort(people.begin(), people.end());
      |     ^~~~
      |     short
foo.cc:42:18: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   42 |     for(int i=0;i<people.size();i++) {
      |                 ~^~~~~~~~~~~~~~