/in/foo.cc: In function 'int main()':
/in/foo.cc:34:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(int i = 0; i < s.size(); i++)
                                ~~^~~~~~~~~~
/in/foo.cc:42:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                     else if(tmp > s[i] && i == s.size() - 1)
                                           ~~^~~~~~~~~~~~~~~
/in/foo.cc:68:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < ans.size(); i++)
                    ~~^~~~~~~~~~~~
/in/foo.cc:24:10: warning: unused variable 'c' [-Wunused-variable]
     char c = getchar();
          ^