Copy on Write is an important concept in computer science that helps boost performance when copying data structures. It might not be something you’ll ever have to implement yourself, but the data strctures (arrays and dictionaries) you use and love do. Therefore, it’s necessary that you understand it so that you know how they work under the hood and how they will behave. And if you ever want to create your own data structure, you don’t get this for free, so check out this episode to learn how to do it.
This is a companion discussion topic for the original entry at https://www.raywenderlich.com/25254417-acing-the-ios-interview/lessons/2