foo.cc: In function 'void standing_by()':
foo.cc:15:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~

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

{"receive":"2020-08-15T17:30:13.315Z","handle":"2020-08-15T17:30:13.315Z","cache_start":"2020-08-15T17:30:13.323Z","read_cases":"2020-08-15T17:30:13.452Z","judge":"2020-08-15T17:30:13.452Z","done":"2020-08-15T17:30:13.794Z"}