/in/foo.cc: In function 'void Output(std::vector<std::vector<int> >&)':
/in/foo.cc:25:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0; i<M.size(); i++)
~^~~~~~~~~
/in/foo.cc:27:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j=0; j<M[i].size(); j++)
~^~~~~~~~~~~~
/in/foo.cc: In function 'void SortRow(std::vector<std::vector<int> >&)':
/in/foo.cc:36:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int k=0; k<M.size(); k++)
~^~~~~~~~~