Examples of commonly used data structures and algorithms in Swift.
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Swift Structures

This project provides a framework for commonly used data structures and algorithms written in a new iOS development language called Swift. While details of many algorithms exists on Wikipedia, these implementations are often written as pseudocode, or are expressed in C or C++. With Swift now officially released, its general syntax should be familiar enough for most programmers to understand.


As a developer, you should already be familiar with the basics of programming. Beyond algorithms, this project also aims to provide an alternative for learning the basics of Swift. This includes implementations of many Swift-specific features such as optionals, extensions, protocols and generics. Beyond Swift, audiences should be familiar with Singleton and Factory design patterns along with sets, arrays and dictionaries.


The project features code-level examples for the following items:

The Book

Now in its 4th edition and supporting Swift 4.2, the The Swift Algorithms Book features code and color illustrations that benefits students and professionals. As a collaborative open-source effort, I also welcome feedback and contribution from others.


    //bfs traversal with inout closure function
    func traverse(_ startingv: Vertex, formula: (_ node: inout Vertex) -> ()) {

        //establish a new queue
        let graphQueue: Queue<Vertex> = Queue<Vertex>()
        //queue a starting vertex
        while !graphQueue.isEmpty() {
            //traverse the next queued vertex - Swift 4.0
            //var vitem: Vertex! = graphQueue.deQueue()
            //traverse the next queued vertex
            guard var vitem = graphQueue.deQueue() else {
            //add unvisited vertices to the queue
            for e in vitem.neighbors {
                if e.neighbor.visited == false {
                    print("adding vertex: \(e.neighbor.key) to queue..")
            //invoke formula

        } //end while
        print("graph traversal complete..")

Getting Started

Swift Structures has been optimized for Swift 4.2 (e.g., Xcode 10.0) or later. The directories are organized as follows:

  • Source - Code for all Swift data structures, algorithms and source extensions
  • Example - An empty iOS single-view application template
  • SwiftTests - Unit tests with XCTest Framework


Individuals are welcome to use the code with commercial and open-source projects. As a courtesy, please provide attribution to waynewbishop.com. For more information, review the complete license agreement.


  • master - The production branch. Clone or fork this repository for the latest copy
  • develop - The active Swift 4.2 development branch. Swift 4.2 pull requests should be directed to this branch

Other Projects

  • EKAlgorithms - A set of computer exercises implemented in Objective-C
  • Algorithms - A playground for common questions implemented in Ruby


Have a question? Feel free to contact me on Twitter or online.