<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 space(string text1, string text2){
        //vector<vector<int>>dp(text1.length()+1 , vector<int>(text2.length()+1 , 0));
        vector<int>curr(text2.length()+1,0);
        vector<int>next(text2.length()+1,0);

        for(int i = text1.length()-1 ; i>=0 ; i--){
            for(int j = text2.length()-1 ; j>= 0 ; j--){
                int ans  = 0;
                if(text1[i] == text2[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 first = s;
        reverse(s.begin() , s.end());
        string second = s;
        return space(first,second);
    }
};
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