foo.cc: In function 'int main()':
foo.cc:6:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("in9.txt","r",stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:7:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("out9.txt","w",stdout);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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

{"receive":"2020-07-27T07:35:49.125Z","handle":"2020-07-27T07:35:49.125Z","cache_start":"2020-07-27T07:35:49.132Z","read_cases":"2020-07-27T07:35:49.273Z","judge":"2020-07-27T07:35:49.275Z","done":"2020-07-27T07:35:49.607Z"}