foo.cc: In function 'long long int read()':
foo.cc:11:17: warning: 'ch' is used uninitialized in this function [-Wuninitialized]
  for(; ch < '0' || ch > '9'; ch = getchar()) if(ch == '-') f = -1;
        ~~~~~~~~~^~~~~~~~~~~

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

{"receive":"2020-07-23T12:19:00.312Z","handle":"2020-07-23T12:19:00.312Z","cache_start":"2020-07-23T12:19:00.318Z","read_cases":"2020-07-23T12:19:00.438Z","judge":"2020-07-23T12:19:00.438Z","done":"2020-07-23T12:19:01.552Z"}