foo.c: In function 'main':
foo.c:7:9: warning: format '%s' expects argument of type 'char *', but argument 2 has type 'char (*)[20000]' [-Wformat=]
 scanf("%s",&a);
         ^
foo.c:12:1: warning: implicit declaration of function 'system' [-Wimplicit-function-declaration]
 system("pause");
 ^~~~~~

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-23T06:48:48.387Z","handle":"2020-02-23T06:48:48.387Z","cache_start":"2020-02-23T06:48:48.387Z","read_cases":"2020-02-23T06:48:48.775Z","judge":"2020-02-23T06:48:48.776Z","done":"2020-02-23T06:48:49.057Z"}