foo.cc:3:28: error: declaration of 'a' as multidimensional array must have bounds for all dimensions except the first
 long long aa(long long a[][],long long b,long long c)
                            ^
foo.cc:3:29: error: expected ')' before ',' token
 long long aa(long long a[][],long long b,long long c)
                             ^
foo.cc:3:30: error: expected unqualified-id before 'long'
 long long aa(long long a[][],long long b,long long c)
                              ^~~~

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