Leetcode 2131: Longest Palindrome by Concatenating Two Letter Words

In this problem, we want to form the longest possible palindrome by concatenating two letter words from a list:

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…