Once Upon an Algorithm: How Stories Explain Computing

Picture a computer scientist, staring at a screen and clicking away frantically on a keyboard, hacking into a system, or perhaps developing an app. Now delete that picture. In Once Upon an Algorithm, Martin Erwig explains computation as something that takes place beyond electronic computers, and computer science as the study of systematic problem solving. Erwig points out that many daily activities involve problem solving. Getting up in the morning, for example: You get up, take a shower, get dressed, eat breakfast. This simple daily routine solves a recurring problem through a series of well-defined steps. In computer science, such a routine is called an algorithm. Erwig illustrates a series of concepts in computing with examples from daily life and familiar stories. Hansel and Gretel, for example, execute an algorithm to get home from the forest. The movie Groundhog Day illustrates the problem of unsolvability; Sherlock Holmes manipulates data structures when solving a crime; the magic in Harry Potter’s world is understood through types and abstraction; and Indiana Jones demonstrates the complexity of searching. Along the way, Erwig also discusses representations and different ways to organize data; “intractable” problems; language, syntax, and ambiguity; control structures, loops, and the halting problem; different forms of recursion; and rules for finding errors in algorithms.

This engaging book explains computation accessibly and shows its relevance to daily life. Something to think about next time we execute the algorithm of getting up in the morning.

Table of Contents

Part I ALGORITHMS
Chapter 1 A Path To Understanding Computation
Chapter 2 Walk The Walk: When Computation Really Happens
Chapter 3 The Mystery Of Signs
Chapter 4 Detective’S Notebook: Accessory After The Fact
Chapter 5 The Search For The Perfect Data Structure
Chapter 6 Sorting Out Sorting
Chapter 7 Mission Intractable

Part II LANGUAGES
Chapter 8 The Prism Of Language
Chapter 9 Finding The Right Tone: Sound Meaning
Chapter 10 Weather, Rinse, Repeat
Chapter 11 Happy Ending Not Guaranteed
Chapter 12 A Stitch In Time Computes Fine
Chapter 13 A Matter Of Interpretation
Chapter 14 The Magical Type
Chapter 15 A Bird’S Eye View: Abstracting From Details