foo.cc: In function 'int main()':
foo.cc:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&p); 
     ~~~~~^~~~~~~~~
foo.cc:10:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d",&s,&t,&n); 
     ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:14:46: 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",&qaq),cont+=((qaq%s)==0); 
                              ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:17:31: 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]); 
                          ~~~~~^~~~~~~~~~~~

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