foo.c:3:5: warning: conflicting types for built-in function 'exit'; expected 'void(int)' [-Wbuiltin-declaration-mismatch]
    3 | int exit(long long c[], long long a, long long num)
      |     ^~~~
foo.c:2:1: note: 'exit' is declared in header '<stdlib.h>'
    1 | #include <stdio.h>
  +++ |+#include <stdlib.h>
    2 | 

[Hydro](https://hydro.ac)提供评测服务