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Leetcode
Medium
Sets
Hash Maps
Design
Design Hashset

Design a data structure that supports insert, remove, and membership checks for integers in average constant time.

Acceptance 0%
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Problem Statement

Problem

Design a hash set from scratch for integer keys.

Implement a class that supports the following operations:

  • add(key): Insert key into the set if it is not already present.
  • remove(key): Remove key from the set if it exists.
  • contains(key): Return true if key exists in the set, otherwise false.

Your implementation should behave like a set: duplicate inserts should not create duplicate entries, and removing a missing key should do nothing.

Goal

Provide an interface with average O(1)O(1) time per operation.

Input Format

  • A sequence of method calls on a hash set instance.
  • Each operation uses one integer key.
  • Keys may be positive, negative, or zero.

Output Format

  • For each membership query, return whether the key is present.
  • Insert and remove operations do not return a value unless specified by the interface.

Constraints

  • Support many operations efficiently.
  • Average time per operation should be constant.
  • Keys are integers and may repeat across operations.

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