/in/foo.cc: In function 'int FindiSecondMax(const std::vector<int>&)':
/in/foo.cc:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < arr.size(); ++i)
                     ~~^~~~~~~~~~~~
/in/foo.cc:29:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < arr.size(); ++i)
                     ~~^~~~~~~~~~~~