Design an algorithm that determines the length of an array A. The only thing the algorithm can do to the array is attempt to obtain the value that is stored at a non-negative index i. Either the attempt will succeed, or it will result in an exception.

Your algorithm must be O(log n), where n is the (unknown) length of A.

a)There will be two distinct phases in your algorithm. In two or three succinct sentences, explain the key ideas behind the first phase.

b)In two or three succinct sentences, explain the key ideas behind the second phase of your algorithm from the previous question.