foo.c: In function 'main':
foo.c:7:14: warning: format '%lf' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
  printf("%.4lf",c); 
              ^

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-21T02:48:34.252Z","handle":"2020-02-21T02:48:34.252Z","cache_start":"2020-02-21T02:48:34.252Z","read_cases":"2020-02-21T02:48:34.445Z","judge":"2020-02-21T02:48:34.448Z","done":"2020-02-21T02:48:34.699Z"}