foo.c:16:1: warning: return type defaults to 'int' [-Wimplicit-int]
 main()
 ^~~~
foo.c: In function 'main':
foo.c:21:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%ld%d",&ran,&num);
  ^~~~~~~~~~~~~~~~~~~~~~~~

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