<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:
    string longestPalindrome(string s) {
        
        int m=0;
        string st="";
        int n=s.length();
        int i=0,j=s.length()-1;
            
            while(i<n)
            {
                if(s[i]==s[j])
                {
                    string su=s.substr(i,j-i+1);
                    string rev=su;
                    reverse(rev.begin(),rev.end());
                    if(su==rev)
                    {
                        if(su.length()>m)
                        {
                            m=su.length();
                            st=su;
                        }
                    }
                }
                if(i==j||j-i+1<m)
                {
                    i++;
                    j=n;
                }
                if(n-i<m)
                {
                    break;
                }
                j--; 
                  
            
        }
        return st;
        
    }
};
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