#### 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
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Index

# Graph traversals

A graph traversal means to visit all the vertices of the graph while keeping track of which nodes or vertices have already been visited and which ones have not. A graph traversal algorithm is efficient if it traverses all the nodes of the graph in the minimum possible time. Graph traversal, also known as a graph search algorithm, is quite similar to the tree traversal algorithms like `preorder`, `inorder`, `postorder`, and level order algorithms; similar to them, in a graph search algorithm we start with a node and traverse through edges to all other nodes in the graph.

A common strategy of graph traversal is to follow a path until a dead end is reached, then traverse back up until there is a point where we meet an alternative path. We can also iteratively move from one node to another in order to traverse the full graph or part of it. Graph traversal algorithms are very important in answering many fundamental problems—they can be useful to determine how to get...