PHP 7 Data Structures and Algorithms

Implementing a binary tree

We will now create a binary tree (not a binary search tree). The key factor to have in a binary tree is that we must have two placeholders for the left child node and the right child node, along with the data we want to store in the node. A simple implementation of a binary node will look like this:

class BinaryNode {     public $data;     public $left;     public $right;     public function __construct(string $data = NULL) {       $this->data = $data;       $this->left = NULL;       $this->right = NULL;     }     public function addChildren(BinaryNode $left, BinaryNode $right) {       $this->left = $left;      $this->right = $right;    }}

The preceding code shows that we have a class with tree properties to store data, left and right. When we are constructing ...