[LeetCode][Python3] 5. Longest Palindromic Substring

Problem :

https://leetcode.com/problems/longest-palindromic-substring/

My Solution :

class Solution:

def longestPalindrome(self, s: str) -> str:

L, R = 0, len(s)

def expand(left, right):

while L <= left and right < R and s[left] == s[right]:

left -= 1

right += 1

return right - left - 1

ans = ''

for i in range(len(s)):

size = max(expand(i, i), expand(i, i+1))

if size > len(ans):

ans = s[i-(size-1)//2:i+1+size//2]

return ans