foo.c:4:5: error: conflicting types for 'remove'
 int remove(int a[], int n, int k) {
     ^~~~~~
In file included from foo.c:1:0:
/usr/include/stdio.h:144:12: note: previous declaration of 'remove' was here
 extern int remove (const char *__filename) __THROW;
            ^~~~~~
foo.c: In function 'main':
foo.c:34:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n1, &n2);
  ^~~~~~~~~~~~~~~~~~~~~~~~
foo.c:38:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ^~~~~~~~~~~~~~~~~~
foo.c:41:3: 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