HashSet

A HashSet is a data structure used in computer programming to store unique items efficiently. It works like a collection where each item is stored in such a way that the system can quickly check if an item already exists, without duplicates. Think of it as a highly organized digital box that automatically keeps only one copy of each item, making it fast to add, remove, or verify presence of elements. HashSets are useful when you need to ensure uniqueness and perform rapid membership tests, common in applications like managing tags, removing duplicates, or tracking visited items.