foo.c: In function 'main':
foo.c:7:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(a);
  ^~~~
In file included from foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
foo.c:10:4: warning: array subscript has type 'char' [-Wchar-subscripts]
   b[a[i]]++;
    ^
foo.c:14:14: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(b[max]<b[a[i]])
              ^
foo.c:19:14: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(b[min]>b[a[i]])
              ^
/tmp/ccbYGInQ.o: In function `main':
foo.c:(.text.startup+0xf): warning: the `gets' function is dangerous and should not be used.

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-23T07:33:01.500Z","handle":"2020-02-23T07:33:01.500Z","cache_start":"2020-02-23T07:33:01.500Z","read_cases":"2020-02-23T07:33:01.677Z","judge":"2020-02-23T07:33:01.678Z","done":"2020-02-23T07:33:02.111Z"}