#### Overview of this book

Data structures allow you to store and organize data efficiently. They are critical to any problem, provide a complete solution, and act like reusable code. Hands-On Data Structures and Algorithms with Python teaches you the essential Python data structures and the most common algorithms for building easy and maintainable applications. This book helps you to understand the power of linked lists, double linked lists, and circular linked lists. You will learn to create complex data structures, such as graphs, stacks, and queues. As you make your way through the chapters, you will explore the application of binary searches and binary search trees, along with learning common techniques and structures used in tasks such as preprocessing, modeling, and transforming data. In the concluding chapters, you will get to grips with organizing your code in a manageable, consistent, and extendable way. You will also study how to bubble sort, selection sort, insertion sort, and merge sort algorithms in detail. By the end of the book, you will have learned how to build components that are easy to understand, debug, and use in different applications. You will get insights into Python implementation of all the important and relevant algorithms.
Preface
Free Chapter
Python Objects, Types, and Expressions
Python Data Types and Structures
Principles of Algorithm Design
Lists and Pointer Structures
Stacks and Queues
Trees
Hashing and Symbol Tables
Graphs and Other Algorithms
Searching
Sorting
Selection Algorithms
String Algorithms and Techniques
Design Techniques and Strategies
Implementations, Applications, and Tools
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# Terminology

Let's consider some terminology associated with tree data structures.

To understand trees, we need to first understand the basic concepts related to them. A tree is a data structure in which data is organized in a hierarchical form. The following diagram contains a typical tree consisting of character nodes lettered A through to M:

Here is a list of terms associated with a tree:

• Node: Each circled letter in the preceding diagram represents a node. A node is any data structure that actually stores the data.
• Root node: The root node is the first node from which all other nodes in the tree are attached. In every tree, there is always one unique root node. The root node in our example tree is node A.
• Sub-tree: A sub-tree of a tree is a tree with its nodes being a descendant of some other tree. For example, nodes F, K, and L form a sub-tree of the original tree consisting...