foo.cc:3:41: error: ISO C++ forbids declaration of 'aa' with no type [-fpermissive]
 aa(long long a[],long long b,long long c)
                                         ^
foo.cc: In function 'int aa(long long int*, long long int, long long int)':
foo.cc:13:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。