Longest Palindromic Subsequence

You are given a string s, find the longest palindromic subsequence's length in s.

A subsequence is a sequence that can be derived from another sequence by deleting some or no elements without changing the order of the remaining elements.

Example 1:

Input: s = "bbbab"

Output: 4

Explanation: One possible longest palindromic subsequence is "bbbb".

Example 2:

Input: s = "cbbd"

Output: 2

Explanation: One possible longest palindromic subsequence is "bb".

Constraints:

• 1 <= s.length <= 1000
• s consists only of lowercase English letters.