1771 - Maximize Palindrome Length From Subsequences\.

Hard

You are given two strings, word1 and word2. You want to construct a string in the following manner:

• Choose some non-empty subsequence subsequence1 from word1.

• Choose some non-empty subsequence subsequence2 from word2.

• Concatenate the subsequences: subsequence1 + subsequence2, to make the string.

Return the length of the longest palindrome that can be constructed in the described manner. If no palindromes can be constructed, return 0.

A subsequence of a string s is a string that can be made by deleting some (possibly none) characters from s without changing the order of the remaining characters.

A palindrome is a string that reads the same forward as well as backward.

Example 1:

Input: word1 = "cacb", word2 = "cbba"

Output: 5

Explanation: Choose "ab" from word1 and "cba" from word2 to make "abcba", which is a palindrome.

Example 2:

Input: word1 = "ab", word2 = "ab"

Output: 3

Explanation: Choose "ab" from word1 and "a" from word2 to make "aba", which is a palindrome.

Example 3:

Input: word1 = "aa", word2 = "bb"

Output: 0

Explanation: You cannot construct a palindrome from the described method, so return 0.

Constraints:

• 1 <= word1.length, word2.length <= 1000

• word1 and word2 consist of lowercase English letters.