/in/foo.cc: In function 'bool has_saddle_point(std::vector<std::vector<int> >&)':
/in/foo.cc:6:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    6 |     for (int row = 0; row < matrix.size(); ++row) {
      |                       ~~~~^~~~~~~~~~~~~~~
/in/foo.cc:9:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |         for (int col = 1; col < matrix[row].size(); ++col) {
      |                           ~~~~^~~~~~~~~~~~~~~~~~~~
/in/foo.cc:16:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |         for (int r = 0; r < matrix.size(); ++r) {
      |                         ~~^~~~~~~~~~~~~~~