/in/foo.cc: In function 'int billy()':
/in/foo.cc:86:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<p[cur].size();i++)
                     ~^~~~~~~~~~~~~~
/in/foo.cc:92:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<p[u].size();i++)
                     ~^~~~~~~~~~~~
/in/foo.cc:95:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<p[d].size();i++)
                     ~^~~~~~~~~~~~
/in/foo.cc: At global scope:
/in/foo.cc:100:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^