Code RoomShortest palindrome by prepending
HardPrep Room Coding #732

Shortest palindrome by prepending

CodingAlgorithms & data structuresSenior–Staff~35 min

You may only PREPEND characters to the front of s. Return the shortest palindrome obtainable this way. For example "aacecaaa" becomes "aaacecaaa" and "abcd" becomes "dcbabcd". An already-palindromic string is returned unchanged, and the empty string returns the empty string. Strings can be up to 10^5 characters, so an O(n) approach using the KMP failure function on s + sentinel + reverse(s) is intended.

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.

0:00 of about 35 min
InputExpectedGot
["aacecaaa"]"aaacecaaa"not run yetsample