Randomized Set in O(1) | Dataford Interview Questions

Hive's activity surfaces need a collection of unique activity IDs that supports fast updates and uniform random selection. Implement a randomized set with constant average-time insertion, deletion, and random retrieval.

Your function receives an ordered list of operations and a random seed for reproducible evaluation. Each operation is represented as a two-element array: ["insert", value], ["remove", value], or ["getRandom"]. Return one result per operation. insert and remove return a boolean indicating whether the set changed. getRandom returns one uniformly selected value from the current set. The input will not request getRandom when the set is empty.

Use a hash map and a dynamic array. The public operation-processing function should use a randomized set internally.

Constraints

1 <= operations.length <= 10^5
-10^9 <= value <= 10^9
Values are integers
getRandom is called only when the set is non-empty
Each operation must run in average O(1) time

Function Signature

def randomized_set(operations, seed):

Your question is Randomized Set in O(1). Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Use a hash map and a dynamic array. The public operation-processing function should use a randomized set internally.

Constraints

1 <= operations.length <= 10^5
-10^9 <= value <= 10^9
Values are integers
getRandom is called only when the set is non-empty
Each operation must run in average O(1) time

Function Signature

def randomized_set(operations, seed):

Your question is Randomized Set in O(1). Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.