Code RoomLongest happy prefix
MediumPrep Room Coding #946

Longest happy prefix

CodingAlgorithms & data structuresMid–Senior~20 min

A 'happy prefix' is a non-empty prefix of a string that is also a (proper) suffix, excluding the whole string itself. Given a string s of lowercase letters (1 <= len(s) <= 10^5), return the longest happy prefix. Return the empty string if none exists.

Implement
longest_happy_prefix(s: str) → str
Examples
in["level"]out"l"
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 20 min
InputExpectedGot
["level"]"l"not run yetsample