Preface

Welcome to Hands On Data Structures! Basically, data structures are the cornerstone in computer science as all operations in computer are virtually to manipulate data efficiently.

So, what is a data structure exactly? Wikipedia offers a working definition:

In computer science, a data structure is a data organization, management, and storage format that is usually chosen for efficient access to data.

Suppose you are a librarian and there are more than 10 thousand books. Then how to organize and manage those books is of importance to you, because readers expects they are able to find the book they love efficiently. Nobody wants a mess!

In this book, you will learn to organize/manage those data (e.g., books) by designing efficient data structures. Let's stick to the analogy of being a librarian. As we can see, how to fetch/add/remove books is also an essential part of your daily work. In computer science, it is called algorithms, which describes how to do something step by step in computers. Furthermore, we can obtain such interesting equation¹:

\[ Programs = Data\ Structures + Algorithms \]

It is obvious that data structures and algorithms are highly inherently relevant with each other. Without data structures, it is unlikely to design efficient algorithms. To some extent, algorithms can be regarded the application of data structures. However, a thorough introduction to algorithms, mainly including algorithms design and analysis, is out of the scope of this book. As a result, we focus on some basic data structures, and only a handful of parts are dedicated to pure algorithms.

Note that there are many awesome books available about data structures and algorithms, and this book is just a follower of them. Just to name a few:

• Introduction to Algorithms by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein. It is known as CLRS.
• Algorithms by Robert Sedgewick, Kevin Wayne.
• Data Structures & Algorithms in Java by Michael T. Goodrich, Roberto Tamassia, Michael H. Goldwasser.
• Data Structures & Algorithms in Python by Michael T. Goodrich, Roberto Tamassia, Michael H. Goldwasser.
• Data Structures and Algorithm Analysis in Java by Mark A. Weiss.

It is highly recommended reading those masterpieces (especially CLRS and Algorithms) if you want to have an in-depth understanding, for this book is tailored for students in SWUFE by eliminating or simplifying many obscure parts.

The motivation of this book is to help students obtain hands-on skills in terms of data structures by putting emphasis on coding and programming itself. It is also worthwhile to note that data structures are not limited to some specific programming languages. In this book, we will focus on the object-oriented way, and cover the implementations in both Java and Python.

¹ Algorithms + Data Structures = Programs is a 1976 book written by Niklaus Wirth covering some of fundamental topics of computer programming, particularly that algorithms and data structures are inherently related.