<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:
        L=[]
        for i in range(len(s)):
            st=s[i]
            l,r=i-1,i+1
            while l>=0 and r<len(s):
                if s[l]==s[r]:
                    st=s[l]+st+s[r]
                    l-=1
                    r+=1
                elif s[l]==st:
                    st=s[l]+st
                    l-=1
                elif s[r]==st:
                    st+=s[r]
                    r+=1
                else:
                    break
            L.append(st)
        for i in range(len(s)-1):
            if s[i]==s[i+1]:
                st=s[i]+s[i+1]
                l,r=i-1,i+2
                while l>=0 and r<len(s):
                    if s[l]==s[r]:
                        st=s[l]+st+s[r]
                        l-=1
                        r+=1
                    elif s[l]==st:
                        st=s[l]+st
                        l-=1
                    elif s[r]==st:
                        st+=s[r]
                        r+=1
                    else:
                        break
                L.append(st)
                
        print(L)
        L.sort(key=lambda x: len(x))
        return L[-1]
20000