foo.cc: In function 'int main()':
foo.cc:69:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("input.in", "r", stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:70:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("output.out", "w", stdout);
  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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

{"receive":"2020-07-16T12:02:36.731Z","handle":"2020-07-16T12:02:36.731Z","cache_start":"2020-07-16T12:02:36.737Z","read_cases":"2020-07-16T12:02:36.858Z","judge":"2020-07-16T12:02:36.872Z","done":"2020-07-16T12:02:38.836Z"}