/in/foo.cc: In function 'int main()':
/in/foo.cc:74:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j=0;j<ans[i].size();j++)
                          ~^~~~~~~~~~~~~~
/in/foo.cc:76:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 printf("%d%c",ans[i][j],"=\n"[j==ans[i].size()-1]);
                                               ~^~~~~~~~~~~~~~~~~