CodingHardcod-g372

Subject KmpLevel Senior–Staff~30 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a string s, you may add characters in front of it to make it a palindrome. Return the shortest palindrome you can form by performing this transformation. s consists of lowercase English letters and may be empty (0 <= len(s) <= 5*10^4), so an O(n) approach is expected.

Implement

shortest_palindrome(s: str) → str

Examples

in["aacecaaa"]out"aaacecaaa"

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.