/in/foo.cc: In function 'int check_1(int)':
/in/foo.cc:59:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0;i<num.size();i++)
               ~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:74:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<num.size();i++)
                ~^~~~~~~~~~~
/in/foo.cc:86:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j=0;j<num.size();j++)
                 ~^~~~~~~~~~~
/in/foo.cc:98:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<num.size();i++)
                ~^~~~~~~~~~~
/in/foo.cc:110:27: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<int>::size_type {aka long unsigned int}' [-Wformat=]
   printf("%d\n",ans.size());
                           ^
/in/foo.cc:111:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<ans.size();i++)
                ~^~~~~~~~~~~