#### 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

# The Knuth-Morris-Pratt algorithm

The KMP algorithm is a pattern matching algorithm based on the idea that the overlapping text in the pattern itself can be used to immediately know at the time of any mismatch how much the pattern should be shifted to skip unnecessary comparisons. In this algorithm, we will precompute the `prefix` function that indicates the required number of shifts of the pattern whenever we get a mismatch. The KMP algorithm preprocesses the pattern to avoid unnecessary comparisons using the `prefix` function. So, the algorithm utilizes the `prefix` function to estimate how much the pattern should be shifted to search the pattern in the text string whenever we get a mismatch. The KMP algorithm is efficient as it minimizes the number of comparisons of the given patterns with respect to the text string.

The motivation behind the KMP algorithm can be observed in Figure 13.4. In this example, it can be seen that the mismatch occurred at the 6th position with the last character...