/in/foo.cc:7:28: error: expected ')' before '::' token
 __asm__("movl %0, %%esp\n" :: "r"(p));
                            ^~
/in/foo.cc: In function 'void dfs(int, int)':
/in/foo.cc:19:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<e[x].size();i++)
              ~^~~~~~~~~~~~