foo.c: In function 'main':
foo.c:7:6: warning: variable 'b' set but not used [-Wunused-but-set-variable]
  int b[100];
      ^
foo.c:4:6: warning: unused variable 'min' [-Wunused-variable]
  int min;
      ^~~
foo.c:10:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&a[i]);
  ^~~~~~~~~~~~~~~~~
foo.c:5:6: warning: 'mark' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int mark;
      ^~~~

[Hydro](https://hydro.ac)提供评测服务