public class Solution
extends Object
2131 - Longest Palindrome by Concatenating Two Letter Words\.
Medium
You are given an array of strings `words`. Each element of `words` consists of **two** lowercase English letters.
Create the **longest possible palindrome** by selecting some elements from `words` and concatenating them in **any order**. Each element can be selected **at most once**.
Return _the **length** of the longest palindrome that you can create_. If it is impossible to create any palindrome, return `0`.
A **palindrome** is a string that reads the same forward and backward.
**Example 1:**
**Input:** words = ["lc","cl","gg"]
**Output:** 6
**Explanation:** One longest palindrome is "lc" + "gg" + "cl" = "lcggcl", of length 6. Note that "clgglc" is another longest palindrome that can be created.
**Example 2:**
**Input:** words = ["ab","ty","yt","lc","cl","ab"]
**Output:** 8
**Explanation:** One longest palindrome is "ty" + "lc" + "cl" + "yt" = "tylcclyt", of length 8. Note that "lcyttycl" is another longest palindrome that can be created.
**Example 3:**
**Input:** words = ["cc","ll","xx"]
**Output:** 2
**Explanation:** One longest palindrome is "cc", of length 2. Note that "ll" is another longest palindrome that can be created, and so is "xx".
**Constraints:**
* 1 <= words.length <= 105
* `words[i].length == 2`
* `words[i]` consists of lowercase English letters.