foo.cc: In function 'int main()':
foo.cc:39:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d",&n,&m1,&m2);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:44:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&u,&v);
   ~~~~~^~~~~~~~~~~~~~
foo.cc:49:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&u,&v);
   ~~~~~^~~~~~~~~~~~~~

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

{"receive":"2020-07-21T07:49:17.308Z","handle":"2020-07-21T07:49:17.308Z","cache_start":"2020-07-21T07:49:17.315Z","read_cases":"2020-07-21T07:49:17.440Z","judge":"2020-07-21T07:49:17.441Z","done":"2020-07-21T07:49:18.071Z"}