Book Image

Swift Data Structure and Algorithms

By : Mario Eguiluz Alebicto
Book Image

Swift Data Structure and Algorithms

By: Mario Eguiluz Alebicto

Overview of this book

Apple’s Swift language has expressive features that are familiar to those working with modern functional languages, but also provides backward support for Objective-C and Apple’s legacy frameworks. These features are attracting many new developers to start creating applications for OS X and iOS using Swift. Designing an application to scale while processing large amounts of data or provide fast and efficient searching can be complex, especially running on mobile devices with limited memory and bandwidth. Learning about best practices and knowing how to select the best data structure and algorithm in Swift is crucial to the success of your application and will help ensure your application is a success. That’s what this book will teach you. Starting at the beginning, this book will cover the basic data structures and Swift types, and introduce asymptotic analysis. You’ll learn about the standard library collections and bridging between Swift and Objective-C collections. You will see how to implement advanced data structures, sort algorithms, work with trees, advanced searching methods, use graphs, and performance and algorithm efficiency. You’ll also see how to choose the perfect algorithm for your problem.
Table of Contents (15 chapters)
Swift Data Structure and Algorithms
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface

AVL trees


Invented by Georgy Adelson-Velski and Evgenii Landis, and named with their initials, AVL trees were the first self-balance binary search tree created.

AVL tree's special characteristic is if the height of a node subtree is N, the height of the other subtree of the same node must be in the range [N-1, N+1]. This means that heights of both children should differ at most one.

For example, if the height of the right subtree is 3, the height of the left subtree could be 2, 3, or 4. The difference between both heights is called the Balance factor:

Balance factor = Height(RightSubtree) - Height(LeftSubtree)

AVL tree example with balance factors of each node

In the preceding figure, the balance factor of a valid AVL tree is in the range [-1, 1] for every node. Leaves have a balance factor of 0.

  • If Balance factor is < 0, the node is called left heavy

  • If Balance factor is = 0, the node is called balanced

  • If Balance factor is > 0, the node is called right heavy

If a child subtree doesn...