Code RoomRemove duplicate letters
MediumPrep Room Coding #1184

Remove duplicate letters

CodingAlgorithms & data structuresMid–Senior~26 min

Given a string s of lowercase letters, remove duplicate letters so that every letter appears exactly once and the result is the lexicographically smallest string among all such results (preserving relative order of the kept letters). 1 <= len(s) <= 10000. Example: 'cbacdcbc' -> 'acdb'.

Implement
remove_duplicate_letters(s: str) → str
Examples
in["cbacdcbc"]out"acdb"
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 26 min
InputExpectedGot
["cbacdcbc"]"acdb"not run yetsample