Book Image

Python Data Structures and Algorithms

By : Benjamin Baka
Book Image

Python Data Structures and Algorithms

By: Benjamin Baka

Overview of this book

Data structures allow you to organize data in a particular way efficiently. They are critical to any problem, provide a complete solution, and act like reusable code. In this book, you will learn the essential Python data structures and the most common algorithms. With this easy-to-read book, you will be able to understand the power of linked lists, double linked lists, and circular linked lists. You will be able to create complex data structures such as graphs, stacks and queues. We will explore the application of binary searches and binary search trees. You will learn the common techniques and structures used in tasks such as preprocessing, modeling, and transforming data. We will also discuss how to organize your code in a manageable, consistent, and extendable way. The book will explore in detail sorting algorithms such as bubble sort, selection sort, insertion sort, and merge sort. By the end of the book, you will learn how to build components that are easy to understand, debug, and use in different applications.
Table of Contents (20 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
5
Stacks and Queues
7
Hashing and Symbol Tables

Selection sort


Another popular sorting algorithm is the selection sort. This sorting algorithm is simple to understand, yet also inefficient, with its worst and best asymptotic values being O(n2). It begins by finding the smallest element in an array and interchanging it with data at, for instance, array index [0]. The same operation is done a second time; however, the smallest element in the remainder of the list after finding the first smallest element is interchanged with the data at index [1].

In a bid to throw more light on how the algorithm works, lets sort a list of numbers:

Starting at index 0, we search for the smallest item in the list that exists between index 1 and the index of the last element. When this element has been found, it is exchanged with the data found at index 0. We simply repeat this process until the list becomes sorted.

Searching for the smallest item within the list is an incremental process:

A comparison of elements 2 and 5 selects 2 as the lesser of the two. The...