Code RoomSmallest number after deletions
MediumPrep Room Coding #650

Smallest number after deletions

CodingAlgorithms & data structuresEntry–Mid~16 min

Given a string of digits num (no sign, possibly with leading zeros after deletions) and an integer k, delete exactly k digits so that the remaining digits, kept in order, read as the smallest possible number. Return that number as a string without unnecessary leading zeros; return '0' if nothing remains or only zeros remain. Example: num '1432219' with k = 3 gives '1219'.

Implement
smallest_after_removals(num: str, k: int) → str
Examples
in["1432219",3]out"1219"
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 16 min
InputExpectedGot
["1432219",3]"1219"not run yetsample