Coding·60 minMembers

Lottery System / Insert Delete GetRandom O(1)

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Design a data structure for a lottery that supports adding a participant, removing a participant, and randomly picking a winner — all in O(1). Appears framed both as the classic LeetCode problem and a...

SWE

data-structure

hashmap

array

sampling

medium

Frequency

Low

Last asked

2026-01-22

Stage

phone-screen · onsite-coding

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