foo.cc: In function ‘void solve()’:
foo.cc:27:21: warning: comparison of integer expressions of different signedness: ‘long long int’ and ‘std::vector<long long int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   27 |     for(int i = 0;i < a.size();i++){
      |                   ~~^~~~~~~~~~
foo.cc:28:25: warning: comparison of integer expressions of different signedness: ‘long long int’ and ‘std::vector<long long int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   28 |         for(int j = 0;j < b.size();j++){
      |                       ~~^~~~~~~~~~