SwiftSets is an exploration: implementing new data structures in Swift with the same features that first-party structures like Array and Dictionary enjoy. Set is the first implementation.

Set: an unordered collection of unique values with O(1) lookup for set membership. For more information about the creation of this type, see this post.

CountedSet: based on Set, and with inspirations from NSCountedSet, each element in a CountedSet has an associated counter, keeping track of how many times the element has been added into the set.

SwiftSets is (c) 2014 Nate Cook and available under the MIT license.