/in/foo.cc: In function 'void dfs(int, int)':
/in/foo.cc:17:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<g[x].size();i++)
                ~^~~~~~~~~~~~
/in/foo.cc:24:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0;i<g[x].size();i++)
                ~^~~~~~~~~~~~