/in/foo.cc: In function 'void work(node&, int, std::__cxx11::string)':
/in/foo.cc:16:6: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(i>=s.size()) return;
     ~^~~~~~~~~~
/in/foo.cc:18:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(;i<s.size();i+=1)
       ~^~~~~~~~~
/in/foo.cc:21:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j=0;j<p.to.size();j+=1)
              ~^~~~~~~~~~~~