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)

Backtracking to solve puzzle problem

Backtracking is a recursive algorithm strategy where we backtrack when a result is not found and continue search for solution in other possible ways. Backtracking is a popular way to solve many famous problems, especially chess, Sudoku, crosswords, and so on. Since recursion is the key component of backtracking, we need to ensure that our problem can be divided into sub problems, and we apply recursion into those sub problems. In this section, we will solve one of the most popular games, Sudoku, using backtracking.

In Sudoku, we have a partially filled box with nice boxes of size 3X3. The rule of the game is to place a number 1 to 9 in each cell, where the same number cannot exist in the same row or column. So, in the 9X9 cell, each number 1 to 9 will be present only once for each row and each column:

...

7

3

8

2

5