foo.cc: In function 'int main()':
foo.cc:23:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
foo.cc:25:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%ld", &arr[i].u);
   ~~~~~^~~~~~~~~~~~~~~~~~
foo.cc:27:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%ld", &arr[i].v);
   ~~~~~^~~~~~~~~~~~~~~~~~

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

{"receive":"2020-07-11T10:35:05.662Z","handle":"2020-07-11T10:35:05.677Z","cache_start":"2020-07-11T10:35:05.773Z","read_cases":"2020-07-11T10:35:06.138Z","judge":"2020-07-11T10:35:06.147Z","done":"2020-07-11T10:35:07.472Z"}