foo.cc: In function 'int main()':
foo.cc:56:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~
foo.cc:57:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1;i<=n;i++) scanf("%d",&a[i]);
                           ~~~~~^~~~~~~~~~~~
foo.cc:72:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&l,&r);
         ~~~~~^~~~~~~~~~~~~~

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

{"receive":"2020-08-12T14:08:48.462Z","handle":"2020-08-12T14:08:48.462Z","cache_start":"2020-08-12T14:08:48.516Z","read_cases":"2020-08-12T14:08:48.716Z","judge":"2020-08-12T14:08:48.723Z","done":"2020-08-12T14:08:50.909Z"}