/in/foo.cc: In function 'bool has_downward_motive(const std::vector<int>&)':
/in/foo.cc:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i < notes.size() - 1; ++i)
                     ~~^~~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'bool is_very_flat(const std::vector<int>&)':
/in/foo.cc:26:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i < notes.size() - 1; ++i)
                     ~~^~~~~~~~~~~~~~~~~~