LinkedHashSet

LinkedHashSet is a Set that remembers the order in which its elements were inserted. It provides the same uniqueness guarantee and the same average O(1) add, remove, and contains as HashSet, but iterating over it walks elements in the order they were first added rather than in some scrambled hash order. This lesson covers what changes underneath when insertion order is preserved, the cost of that extra bookkeeping, the common e-commerce use cases (recently viewed unique products, unique browsed categories, applied coupon codes in the order they were entered), and how LinkedHashSet compares to HashSet and TreeSet.