<p>Given a string <code>s</code>, find <em>the longest palindromic <strong>subsequence</strong>&#39;s length in</em> <code>s</code>.</p>

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

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;bbbab&quot;
<strong>Output:</strong> 4
<strong>Explanation:</strong> One possible longest palindromic subsequence is &quot;bbbb&quot;.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;cbbd&quot;
<strong>Output:</strong> 2
<strong>Explanation:</strong> One possible longest palindromic subsequence is &quot;bb&quot;.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 1000</code></li>
	<li><code>s</code> consists only of lowercase English letters.</li>
</ul>

class Solution:
    def longestPalindromeSubseq(self, s: str) -> int:
        dp=[[-1 for i in range(len(s))] for j in range(len(s))]
        n=len(s)
        dp=[[-1 for i in range(n+1)] for j in range(n+1)]
        def check(i,j):
            if i==j:
                return 1 if s[i]==s[j] else 0
            if i>j:
                return 0
            if dp[i][j]!=-1:
                return dp[i][j]
            if s[i]==s[j]:
                cnt=2+check(i+1,j-1)
            else:
                left=check(i+1,j)
                right=check(i,j-1)
                cnt=max(left,right)
            dp[i][j]=cnt
            return cnt
        return check(0,n-1)
                
71418