2002 - Maximum Product of the Length of Two Palindromic Subsequences.

Medium

Given a string s, find two disjoint palindromic subsequences of s such that the product of their lengths is maximized. The two subsequences are disjoint if they do not both pick a character at the same index.

Return the maximum possible product of the lengths of the two palindromic subsequences.

A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters. A string is palindromic if it reads the same forward and backward.

Example 1:

Input: s = "leetcodecom"

Output: 9

Explanation: An optimal solution is to choose "ete" for the 1^st subsequence and "cdc" for the 2^nd subsequence.

The product of their lengths is: 3 \* 3 = 9.

Example 2:

Input: s = "bb"

Output: 1

Explanation: An optimal solution is to choose "b" (the first character) for the 1^st subsequence and "b" (the second character) for the 2^nd subsequence.

The product of their lengths is: 1 \* 1 = 1.

Example 3:

Input: s = "accbcaxxcxx"

Output: 25

Explanation: An optimal solution is to choose "accca" for the 1^st subsequence and "xxcxx" for the 2^nd subsequence.

The product of their lengths is: 5 \* 5 = 25.

Constraints:

• 2 <= s.length <= 12

• s consists of lowercase English letters only.