#### Overview of this book

Choosing the right data structure is pivotal to optimizing the performance and scalability of applications. This new edition of Hands-On Data Structures and Algorithms with Python will expand your understanding of key structures, including stacks, queues, and lists, and also show you how to apply priority queues and heaps in applications. You’ll learn how to analyze and compare Python algorithms, and understand which algorithms should be used for a problem based on running time and computational complexity. You will also become confident organizing your code in a manageable, consistent, and scalable way, which will boost your productivity as a Python developer. By the end of this Python book, you’ll be able to manipulate the most important data structures and algorithms to more efficiently store, organize, and access data in your applications.
Preface
Free Chapter
Python Data Types and Structures
Introduction to Algorithm Design
Algorithm Design Techniques and Strategies
Stacks and Queues
Trees
Heaps and Priority Queues
Hash Tables
Graphs and Algorithms
Searching
Sorting
Selection Algorithms
String Matching Algorithms
Other Books You May Enjoy
Index

# Terminology

Let’s consider some of the 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.

Figure 6.1 contains a typical tree consisting of character nodes lettered `A` through to `M`:

Figure 6.1: Example tree data structure

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 stores data.
• Root node: The root node is the first node from which all other nodes in the tree descend from. In other words, a root node is a node that does not have a parent node. In every tree, there is always one unique root node. The root node is node `A` in the above example tree.
• Subtree: A subtree is a tree whose nodes descend from some other tree. For example, nodes `F`, `K`, and `L` form a subtree of the...