/in/foo.cc: In function 'int main()':
/in/foo.cc:136:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (j=0;j<ansx[i].size();j++){
            ~^~~~~~~~~~~~~~~
/in/foo.cc:145:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (j=0;j<ansy[i].size();j++){
            ~^~~~~~~~~~~~~~~