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JavaIntermediate#collections
JavaIntermediate#collections
What is the difference between Set implementations HashSet, LinkedHashSet, and TreeSet?
HashSet offers O(1) operations with no ordering guarantee. LinkedHashSet maintains insertion order using a backing linked list. TreeSet keeps elements sorted (natural order or a Comparator) using a red-black tree, with O(log n) operations.
Example
Set<Integer> hs = new HashSet<>(List.of(3,1,2)); // unordered Set<Integer> lhs = new LinkedHashSet<>(List.of(3,1,2)); // [3,1,2] Set<Integer> ts = new TreeSet<>(List.of(3,1,2)); // [1,2,3]