foo.cc: In function ‘void solve_1002(int, int, int, std::vector<int>, std::unordered_set<int>, int)’:
foo.cc:39:28: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   39 |             for(int j=i+1;j<pos.size();j++) {
      |                           ~^~~~~~~~~~~