Longest Palindrome Function | Dataford Interview Questions

F5 BIG-IP telemetry can contain compact identifiers and event fragments whose mirrored structure may indicate repeated or malformed data. Given a string, find its longest palindromic substring efficiently.

Return the substring itself. If multiple longest palindromic substrings exist, return the one with the smallest starting index. A substring must use consecutive characters, and matching is case-sensitive.

Formal Specification

Implement longest_palindrome(s), where s is a string containing lowercase English letters. Return a string containing the longest contiguous substring that reads identically forward and backward. Return "" when s is empty.

For the hard version, design an algorithm with O(n) time and O(n) auxiliary space. Do not treat a subsequence as a valid answer.

Constraints

0 <= len(s) <= 10^6
s contains only lowercase English letters
The result must be a contiguous substring of s
If several answers have maximum length, return the one with the smallest starting index

Function Signature

def longest_palindrome(s):

Your question is Longest Palindrome Function. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem