foo.cc: In function 'bool dfs(int)':
foo.cc:17:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < op[t].length(); i++)
                  ~~^~~~~~~~~~~~~~~~
foo.cc:38:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
foo.cc: In function 'int main()':
foo.cc:42:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 0; i < 9; i++) scanf("%d", &dir[i]);
                                 ~~~~~^~~~~~~~~~~~~~~

自豪的采用 HydroJudger 进行评测(github.com/hydro-dev/HydroJudger)

{"receive":"2020-06-24T03:41:20.156Z","handle":"2020-06-24T03:41:20.156Z","done":"2020-06-24T03:41:21.878Z"}