A peak element in an array is the one that is not smaller than its neighbours.
Given an array arr[] of size N, find the index of any one of its peak elements.
Note: The generated output will always be 1 if the index that you return is correct. Otherwise output will be 0. 

Example 1:

Input:
N = 3
arr[] = {1,2,3}
Output: 1
Explanation: index 2 is 3.
It is the peak element as it is 
greater than its neighbour 2.

Example 2:

Input:
N = 2
arr[] = {3,4}
Output: 1
Explanation: 4 (at index 1) is the 
peak element as it is greater than 
its only neighbour element 3.

Your Task:
You don't have to read input or print anything. Complete the function peakElement() which takes the array arr[] and its size N as input parameters and return the index of any one of its peak elements.

Can you solve the problem in expected time complexity?

Expected Time Complexity: O(log N)
Expected Auxiliary Space: O(1)

Constraints:
1 ≤ N ≤ 10⁵
1 ≤ A[] ≤ 10⁶