#### 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

# The Rabin-Karp algorithm

The Rabin-Karp pattern matching algorithm is an improved version of the brute force approach to find the location of the given pattern in the text string. The performance of the Rabin-Karp algorithm is improved by reducing the number of comparisons with the help of hashing. We discussed the concept of hashing in Chapter 8, Hash Tables. The hashing function returns a unique numeric value for a given string.

This algorithm is faster than the brute force approach as it avoids unnecessary comparisons. In this algorithm, we compare the hash value of the pattern with the hash value of the substring of the text string. If the hash values are not matched, the pattern is shifted forward one position. This is a better algorithm as compared to the brute-force algorithm since there is no need to compare all the characters of the pattern one by one.

This algorithm is based on the concept that if the hash values of the two strings are equal, then it is assumed...