Day32_Longest Palindromic Substring.py

# Longest Palindromic Substring                                Difficulty = Medium

# 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"



class Solution:
    def longestPalindrome(self, s: str) -> str:
        longest = ""
        for i in range(len(s)):
            left = i;right = i
            while left >= 0 and right < len(s) and s[left] == s[right]:left -= 1;right += 1
            palindrome = s[left+1:right]
            if len(palindrome) > len(longest):longest = palindrome
            left = i;right = i+1
            while left >= 0 and right < len(s) and s[left] == s[right]:left -= 1;right += 1
            palindrome = s[left+1:right]  
            if len(palindrome) > len(longest):longest = palindrome
        return longest