# Longest Harmonious Subsequence

Easy
1
36.4% Acceptance

In this lab, you will be working on finding the longest harmonious subsequence within an array of integers. A harmonious array is an array where the difference between its maximum value and its minimum value is exactly `1`. Given an integer array `nums`, your task is to return the length of its longest harmonious subsequence among all its possible subsequences.

A subsequence of array is a sequence that can be derived from the array by deleting some or no elements without changing the order of the remaining elements.

## Examples:

• For `nums = [1,3,2,2,5,2,3,7]`, the longest harmonious subsequence is `[3,2,2,2,3]`, and the output should be `5`.

• For `nums = [1,2,3,4]`, the longest harmonious subsequence is `[1, 2]` or `[3, 4]`, and the output should be `2`.

• For `nums = [1,1,1,1]`, there is no harmonious subsequence, and the output should be `0`.

## Constraints:

• `1 <= nums.length <= 2 * 104`
• `-109 <= nums[i] <= 109`

## Challenges

1. Export a function `findLHS` which takes an argument `nums` and returns the length of its longest harmonious subsequence. Example: `findLHS([1,3,2,2,5,2,3,7])` should return `5`.

2. Test your implementation with varying lengths and values of arrays in `nums`, including arrays with unique elements, arrays with repeating elements, and arrays with negative numbers.