<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 {
public:
int solveTab(string& a, string &b){
    vector<int> curr(b.length()+1, 0);
    vector<int> next(b.length()+1, 0);

    for(int i = a.length()-1; i>=0; i--){
        for(int j = b.length()-1; j>=0; j--){
            int ans = 0;
            if(a[i] == b[j]){
                ans = 1 + next[j+1];
            }
            else{
                ans = max(next[j], curr[j+1]);
            }
            curr[j] = ans;
        }
        next = curr;
    }
   return next[0];
}
    int longestPalindromeSubseq(string s) {
        string revs = s;
        reverse(s.begin(), s.end());

        return solveTab(revs, s);
    }
};
8000