<p>Given a string <code>s</code>, return <em>the longest</em> <span data-keyword="palindromic-string"><em>palindromic</em></span> <span data-keyword="substring-nonempty"><em>substring</em></span> in <code>s</code>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;babad&quot;
<strong>Output:</strong> &quot;bab&quot;
<strong>Explanation:</strong> &quot;aba&quot; is also a valid answer.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;cbbd&quot;
<strong>Output:</strong> &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> consist of only digits and English letters.</li>
</ul>

class Solution {
public:
    void setlongestPalindrome(string s, int index, int& maxCount, string& maxString){
        int count = 1;
        int prev = index - 1;
        int next = index + 1;
        while(prev>=0 && next<s.size()){
            if(s[prev] == s[next]){
                count += 2;
            }else{
                break;
            }
            if(count > maxCount){
                //cout<<s<<endl;
                //cout<<"Odd"<<endl;
                maxString = s.substr(prev, next-prev+1);
                maxCount = count;
                //cout<<maxString<<endl;
            }
            --prev;
            ++next;
        }
        prev = index;
        next = index + 1;
        count = 0;
        while(prev>=0 && next<s.size()){
            if(s[prev] == s[next]){
                count += 2;
            }else{
                break;
            }
            if(count > maxCount){
                //cout<<s<<endl;
                //cout<<"Even"<<endl;
                maxString = s.substr(prev, next-prev+1);
                maxCount = count;
                //cout<<maxString<<endl;
            }
            --prev;
            ++next;
        }
    }
    string longestPalindrome(string s) {
        if(s.empty()){
            return s;
        }
        int maxCount = 1;
        string maxString = s.substr(0,1);
        for(int i=0; i<s.size(); i++){
            setlongestPalindrome(s, i, maxCount, maxString);
        }
        return maxString;
    }
};
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