Longest Subarray with Difference at Most One

Given an array of integers, find the length of the longest subarray (not necessarily contiguous in the original order, but considered as a subset of the array) such that the absolute difference between any two elements is at most 1. In other words, if the subarray is denoted by S, then for every pair of elements a and b in S, it must hold that \(|a - b| \le 1\).

Note: An empty array should return 0. This problem can be solved using a frequency map to count the occurrences of each number and then checking the sums of counts for adjacent numbers (i.e. numbers with difference 1).

inputFormat

The first line contains an integer n, the number of elements in the array. The second line contains n space-separated integers representing the array elements.

outputFormat

Output a single integer representing the length of the longest subarray where the absolute difference between any two elements is at most 1.

6
1 2 2 3 1 2

5