A Hash Set is an unordered collection of unique elements, where elements are stored in a table using a hash function. In my implementation, elements are stored in an Array of Linked Lists.
Quick Facts
- An unordered collection of unique elements.
- Elements in set must be hashable.
- Swift’s Set implementation in Foundation is a Hash Set.
Use Cases
- Test efficiency for membership.
- When not concerned about order of elements.
- When need to ensure elements in collection only appear once.
Structure
Returns true if the set is empty or false if it contains elements.
Returns the number of elements in the set.
func insert(_ element: Element) -> BoolInserts the element into the set the set does not already contain it. Returns true if the element was inserted and false if it was not.
func remove(_ element: Element) -> Element?Removes an element from the set. Returns the element if it is in the set.
func removeAll()Removes all elements from the set.
func contains(_ element: Element) -> Element?Tests for membership. The element is returned if the set contains it.
func union(_ hashSet: HashSet) -> HashSetReturns a new set with the elements of both this set and the given set.
func intersection(_ hashSet: HashSet) -> HashSetReturns a new set with the elements that are common to both this set and the given set.
func difference(_ hashSet: HashSet) -> HashSetRemoves the elements of the given set from this set.
