foo.cc: In function 'int main()':
foo.cc:31:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
foo.cc:34:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%lld", &f[i].a, &f[i].b, &f[i].val);
                                                 ^

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

{"receive":"2020-04-15T15:05:16.947Z","handle":"2020-04-15T15:05:16.947Z","cache_start":"2020-04-15T15:05:16.958Z","read_cases":"2020-04-15T15:05:17.072Z","judge":"2020-04-15T15:05:17.073Z","done":"2020-04-15T15:05:18.426Z"}