foo.c: In function 'main':
foo.c:11:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'long long int *' [-Wformat=]
  scanf("%d %d",&n,&k);
         ~^     ~~
         %lld
foo.c:11:13: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'long long int *' [-Wformat=]
  scanf("%d %d",&n,&k);
            ~^     ~~
            %lld
foo.c:11:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n,&k);
  ^~~~~~~~~~~~~~~~~~~~
foo.c:13:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ^~~~~~~~~~~~~~~~~