/in/foo.cc: In function 'void insert(std::vector<int>&, int)':
/in/foo.cc:7:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |     for (i = 0; i < arr.size(); i++) {
      |                 ~~^~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:31:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for (int j = 0; j < arr.size(); j++) {
      |                     ~~^~~~~~~~~~~~