#### Overview of this book

Learning about data structures and algorithms gives you a better insight on how to solve common programming problems. Most of the problems faced everyday by programmers have been solved, tried, and tested. By knowing how these solutions work, you can ensure that you choose the right tool when you face these problems. This book teaches you tools that you can use to build efficient applications. It starts with an introduction to algorithms and big O notation, later explains bubble, merge, quicksort, and other popular programming patterns. You’ll also learn about data structures such as binary trees, hash tables, and graphs. The book progresses to advanced concepts, such as algorithm design paradigms and graph theory. By the end of the book, you will know how to correctly implement common algorithms and data structures within your applications.
Title Page
Packt Upsell
Contributors
Preface
Free Chapter
Algorithms and Complexities
Sorting Algorithms and Fundamental Data Structures
Hash Tables and Binary Search Trees
String Matching Algorithms
Graphs, Prime Numbers, and Complexity Classes
Other Books You May Enjoy
Index

## Introducing Hash Tables

A data structure that gives us the ability to insert, search, and optionally delete elements in a collection is called a data dictionary. Commonly, the type of data used is a key-value pair association, where we insert the key-value pair but search using a key to obtain the value.

Hash tables provide us with a fast data structure for organizing these key value pairs and implementing our data dictionary. They are useful in a wide variety of applications due to the quick lookup and ease of use for in-memory data storage. Insertion and search operations have a typical average runtime complexity of O(1).

### Understanding Hash Tables

Let's look at an example problem to help us understand the need for hash tables. Imagine you are a teacher, instructing a class of a maximum capacity of 30 students. The students sit at their assigned desks every day. To make your life easier, you decide to assign a sequential number from one to 30 to each desk. You then use this number to identify...