5. Longest Palindromic Substring Palindrome Number | LeetCode Using Python

Have you ever wondered how to efficiently find the longest palindromic substring within a given string? Palindromes are sequences that read the same backward as forward, like “radar” or “madam.”

Code in Python:

class Solution(object):
    def longestPalindrome(self, s):
        """
        :type s: str
        :rtype: str
        """
        
        self.longest_palindromic_substring = "" #return output

        def expansion(i,j):
                #define our conditions
            while i >= 0 and j < len(s) and s[i] == s[j]:
                if j - i + 1 > len(self.longest_palindromic_substring):
                    self.longest_palindromic_substring = s[i:j + 1] #update the longest_palindromic_substring
                    
                i -= 1
                j += 1
            
        #our iteration
        for i in range(len(s)):
            expansion(i, i) #odd numbered input
            expansion(i, i + 1) #for even numbered inputs




        #output
        return self.longest_palindromic_substring