Merge Sort in Swift

The classic sorting algorithm

Photo by Ola Mishchenko on Unsplash

Difficulty: Beginner | Easy | Normal | Challenging

This article covers the classic sorting algorithm Merge Sort, and it’s implementation in Swift.

*This is seen as a beginner topic (first year Computer Science degree fare) but is certainly not easy.

Terminology

Algorithm: A process or set of rules to be followed

Big O Notation: A mathematical notation to describe the limiting behaviour of a function when an argument tends towards infinity

Merge Sort: A sorting algorithm where an array is split into to, sorted and merged back together.

Merge Sort

The merge sort algorithm is a nice algorithm for sorting an array.

The algorithm

Setting up tests

Using the playground, inserting import XCTest and allowing the tests to be run using sortingTests.defaultTestSuite.run() allows us to create tests before creating the solution in Swift.