foo.cc: In function 'void hello()':
foo.cc:56:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("crypt.in","r",stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:57:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("crypt.out","w",stdout);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

正在同步测试数据，请稍后
自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。