foo.cc: In function 'int change(char)':
foo.cc:18:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-17T01:31:25.725Z","handle":"2020-02-17T01:31:25.725Z","cache_start":"2020-02-17T01:31:25.726Z","read_cases":"2020-02-17T01:31:26.740Z","judge":"2020-02-17T01:31:26.747Z","done":"2020-02-17T01:31:29.802Z"}