$1.($use java$)$Divide and conquer

Given an array, $A,$ of $1\text{'}$s and $0\text{'}$s$,$ where the $0\text{'}$s precede the $1\text{'}$s$,$ write an algorithm that

computes their total sum. For example, if $A=[0,0,0,1,1],$ then the sum would be

$0+0+0+1+1=2.$ Make sure that if the size of $A$ is $n,$ your algorithm runs in $O(logn)$ time. Further,

prove the cost of your algorithm.