foo.c: In function 'main':
foo.c:7:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&n);
   ^~~~~~~~~~~~~~
foo.c:8:20: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   for(i=0;i<n;i++) scanf("%d",s+i);
                    ^~~~~~~~~~~~~~~

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