/in/foo.cc: In function 'std::vector<int> merge1(std::vector<int>&, std::vector<int>&)':
/in/foo.cc:19:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         for (int i = 0; i < v2.size(); i++)
      |                         ~~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:34:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |         for (int i = 0; i < h1.size(); i++)
      |                         ~~^~~~~~~~~~~
/in/foo.cc:37:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |         for (int i = 0; i < h2.size(); i++)
      |                         ~~^~~~~~~~~~~