foo.c: In function 'main':
foo.c:19:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n1, &n2);
  ^~~~~~~~~~~~~~~~~~~~~~~
foo.c:21:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ^~~~~~~~~~~~~~~~~~
foo.c:23:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &b[i]);
   ^~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务