Book Image

PHP 7 Data Structures and Algorithms

By : Mizanur Rahman
5 (1)
Book Image

PHP 7 Data Structures and Algorithms

5 (1)
By: Mizanur Rahman

Overview of this book

PHP has always been the the go-to language for web based application development, but there are materials and resources you can refer to to see how it works. Data structures and algorithms help you to code and execute them effectively, cutting down on processing time significantly. If you want to explore data structures and algorithms in a practical way with real-life projects, then this book is for you. The book begins by introducing you to data structures and algorithms and how to solve a problem from beginning to end using them. Once you are well aware of the basics, it covers the core aspects like arrays, listed lists, stacks and queues. It will take you through several methods of finding efficient algorithms and show you which ones you should implement in each scenario. In addition to this, you will explore the possibilities of functional data structures using PHP and go through advanced algorithms and graphs as well as dynamic programming. By the end, you will be confident enough to tackle both basic and advanced data structures, understand how they work, and know when to use them in your day-to-day work
Table of Contents (14 chapters)

Implementing a doubly linked list in PHP

We already know from the definition of a doubly linked list that a doubly linked list node will have two links: one to point to the next node and another to point to the previous node. Also, when we add a new node or delete a new node, we need to set both the next and previous references for each affected nodes. We saw a different approach in the singly linked list implementation where we did not track the last node, and as a result, we had to use an iterator to reach the last node each time. This time, we will track the last node, along with our insert and delete operations, to make sure our insert, and delete, and end operations have O(1) complexity.

Here is how the new node class will look with two link pointers followed by our barebones structure of a doubly linked list class:

class ListNode {

public $data = NULL;
public...