public class Solution
extends Object
594 - Longest Harmonious Subsequence\.
Easy
We define a harmonious array as an array where the difference between its maximum value and its minimum value is **exactly** `1`.
Given an integer array `nums`, 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.
**Example 1:**
**Input:** nums = [1,3,2,2,5,2,3,7]
**Output:** 5
**Explanation:** The longest harmonious subsequence is [3,2,2,2,3].
**Example 2:**
**Input:** nums = [1,2,3,4]
**Output:** 2
**Example 3:**
**Input:** nums = [1,1,1,1]
**Output:** 0
**Constraints:**
* 1 <= nums.length <= 2 * 104
* -109 <= nums[i] <= 109