Given an array arr[] of N Numbers. A Perfect Piece is defined as a subarray such that the difference between the minimum and the maximum value in that range is at most 1. Find the Maximal Length Perfect Piece.

Example 1:
Input:
N = 4
arr[] = {8, 8, 8, 8}
Output:
4
Explanation:
The longest subarray is [1, 4]
where maximum=8 and minimum = 8 and
difference is 0, which is less than 1.
Its length is 4.
Example 2:
Input:
N = 11
arr[] = {5, 4, 5, 5, 6, 7, 8, 8, 8, 7, 6}
Output:
5
Explanation:
The longest subarray is [6, 10]
where maximum=8 and minimum = 7 and
difference is 1. Its length is 5.

Your Task:
You don't need to read input or print anything. Your task is to complete the function longestPerfectPiece() which takes an Integer N and an array arr[] of length N as input and returns the maximal length Perfect Piece.

Expected Time Complexity: O(N*logN)
Expected Auxiliary Space: O(N)

Constraints:
1 <= N <= 10^{5}
1 <= arr[i] <= 10^{5}

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