foo.cc: In function 'int find_rank(int, int)':
foo.cc:114:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
foo.cc: In function 'int find_num(int, int)':
foo.cc:125:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

自豪地采用[jd5](https://github.com/masnn/jd5)进行评测