Implement O(1) randomized multiset
Company: TikTok
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: Medium
Interview Round: Technical Screen
Write code for a data structure that supports add(x), remove(x), and getRandom() in average O(
1) time where duplicates are allowed, and getRandom returns an element with probability proportional to its multiplicity. Explain your design, analyze time/space complexity, and discuss edge cases and randomized testing.
Quick Answer: This question evaluates a candidate's competency in designing and analyzing randomized data structures that support O(1) average-time add, remove, and multiplicity-weighted getRandom operations, emphasizing hashing, index management, and probabilistic reasoning about sampling by multiplicity.