<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:
    
    def longestPalindrome(self, s: str) -> str:
        def isPalin(s11):
            if s11==s11[::-1]:
                return True
            else:
                return False
        l=[]
        t=[0,""]
        for i in range(len(s)+1):
            for j in range(len(s)+1):
                if (j-i)<t[0]:
                    continue
                d=s[i:j]
                if d!="" and isPalin(d):
                    l.append(d)
                    if len(d)>t[0]:
                        t[0]=len(d)
                        t[1]=d
        return t[1]
17100