/in/foo.cc: In function 'int main()':
/in/foo.cc:25:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < major.size(); ++i) {
                    ~~^~~~~~~~~~~~~~
/in/foo.cc:35:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0; j < minor[cur].size(); ++j) {
                        ~~^~~~~~~~~~~~~~~~~~~