Problem

Given a string s, return the longest

palindromic

substring

in

1
s

.

Example 1:

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Input: s = "babad"
Output: "bab"
Explanation: "aba" is also a valid answer.

Example 2:

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Input: s = "cbbd"
Output: "bb"

Constraints:

  • 1 <= s.length <= 1000
  • s consist of only digits and English letters.

Solve

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class Solution:
    def longestPalindrome(self, s: str) -> str:
        res = ""

        for i in range(len(s)):
            # odd

            l , r = i ,  i
            while -1 < l and r < len(s) and s[l] == s[r]:
                if r-l+1 > len(res):
                    res = s[l:r+1]
                l-=1
                r+=1
            l , r = i ,  i+1  
            while -1 < l and r < len(s) and s[l] == s[r]:
                if r-l+1 > len(res):
                    res = s[l:r+1]
                l-=1
                r+=1

        return res