foo.cc: In function ‘bool find(int, std::vector<int>&)’:
foo.cc:6:27: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
    6 |         for (int i = 0; i < vb.size(); i++)
      |                         ~~^~~~~~~~~~~
foo.cc: In function ‘int main()’:
foo.cc:30:27: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   30 |         for (int i = 0; i < vc.size(); i++)
      |                         ~~^~~~~~~~~~~