HashSet

Introduction

Majorly used for tradeoff between Space and time complexities, since it offers exceptional time complexity for a considerable amount of space (CAN USE A TON OF SPACE AT TIMES). High tradeoff between time and space.

Time Complexity

• Insertion: O(1)

• Search: O(1)

• Deletion: O(1)

But how?

Realistically and practically, applications don't use data with ( $n > 2^{64}$ ) (without this assumption the time/space complexities of many data structures would change) [ Quora Answer ]

HashSets are implemented by using hashing functions (refer Hashing) to convert data to integer form. Comparison between integers is, natively, O(1).