Longest Palindromic Substring

Problem

Return the longest palindromic substring of s; when several share the maximum length, return the first one found scanning centers left to right.

Expand around every center, treating both odd-length and even-length palindromes, and keep the longest expansion. Return the empty string for empty input.

Hint

Every palindrome has a center, either one character or a gap between two characters.

Test cases

case 1

in: ["babad"]

expected: "bab"

case 2

in: ["cbbd"]

expected: "bb"

case 3

in: [""]

expected: ""

case 4

in: ["a"]

expected: "a"

case 5

in: ["forgeeksskeegfor"]

expected: "geeksskeeg"

Starter codePython

def longest_palindrome(s):
    # Your code here
    pass

5 test cases · run your code against them in the editor