[LEETCODE] 5. Longest Palindromic Substring

 

 

 

Given a string s, return the longest palindromic substring in s.

Example 1:

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

Example 2:

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

 

Constraints:

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

 

내 풀이

class Solution(object):
    def longestPalindrome(self, s):
 
        res = ""
        for i in range(len(s)):
            res = max(self.helper(s,i,i), self.helper(s,i,i+1), res, key=len)

        return res
       
        
    def helper(self,s,l,r):
        while 0<=l and r < len(s) and s[l]==s[r]:
                l-=1; r+=1
        return s[l+1:r]