foo.cc: In function ‘void solve_problem___()’:
foo.cc:23:25: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   23 |         for(int i = 0;i < a.size();i ++) {
      |                       ~~^~~~~~~~~~
foo.cc:24:33: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   24 |                 for(int j = 0;j < b.size();j ++) {
      |                               ~~^~~~~~~~~~