<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 longestCommonSubsequence(string s1, string s2) {
        if(s1==s2)return s1.size();
    int n1=s1.size();
    int n2=s2.size();
    vector<vector<int>>dp(n1+1,vector<int>(n2+1,0));
    for(int i=1;i<=n1;i++){
        for(int j=1;j<=n2;j++){
            if(s1[i-1]==s2[j-1]){
                dp[i][j]=1+dp[i-1][j-1];
            }
            else{
                dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
            }
        }
    }
    return dp[n1][n2];
    }
    int longestPalindromeSubseq(string s) {
        string s2=s;
        reverse(s2.begin(),s2.end());
       return longestCommonSubsequence(s,s2);
    }
};
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