<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:
    vector<int> expand(string s,int left,int right)
    {
       vector<int> indexes(2,-1);
       while(left>=0 && right<s.length())
       {
         if(s[left]==s[right])
         {
            indexes.clear();
            indexes.push_back(left);
            indexes.push_back(right);
            left--;
            right++;
         }
         else
         {
            break;
         }
       }
       return indexes;
    }
    string longestPalindrome(string s) {
        int n=s.length();
        vector<int> oddL;
        vector<int> evenL;
        int length=0;
        vector<int> ans;
        int start,end;
        for(int i=0;i<n;i++)
        {
          oddL=expand(s,i,i);
          if(oddL[1]-oddL[0]+1>length)
          {
            length=oddL[1]-oddL[0]+1;
            ans.clear();
            ans=oddL;
          }
          evenL=expand(s,i,i+1);
          if(evenL[1]-evenL[0]+1>length)
          {
            length=evenL[1]-evenL[0]+1;
            ans.clear();
            ans=evenL;
          }
        }
        start=ans[0];
        end=ans[1];
        string temp="";
        for(int i=start;i<=end;i++)
        {
           temp+=s[i];
        }
        return temp;
    }
};
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