foo.cc: In function ‘std::vector<int> max_u(std::vector<int>, std::vector<int>)’:
foo.cc:20:27: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
20 | for (int i = 0; i < a.size(); i++)
| ~~^~~~~~~~~~
foo.cc: In function ‘std::vector<int> mul(std::vector<int>, int)’:
foo.cc:34:23: 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 < a.size(); i++)
| ~~^~~~~~~~~~