Consider the following algorithm given in Java code:

int ArrAverage$($int $[]$ Arr$)\{$

int n$=$ Arr.length;

int j;

int k;

int ArrSum $=0$;

int Average $=0$;

If n $=1$:

Average $=($array$[0]+$ array$[1])/2$

return Average

Else:

for $($j $=1$; j $<$ n; j$*=2)$

for $($k $=0$; k $<$ j; k$=$k$+1)$

ArrSum $+=$ array$[$i$]$;

Average $=$ ArrSum $/$ n;

return Average;

$\}$

$($a$)(10$ pts$)$ Give a big$-$Oh for ArrAverage, the worst$-$case running time of this code.Explain how you obtained this worst case.

$($b$)(5$ pts$)$ Give the best$-$case running time of this code. Explain in which scenario you obtained this best case.