<?php

class NodeOfTree
{
    public $tmp;
    public $left;
    public $right;
    public $depth;

    public function __construct($tmp)
    {
        $this->tmp = $tmp;
        $this->left = NULL;
        $this->right = NULL;
        $this->depth = NULL;
    }

    public function __toString()
    {
        return "$this->tmp";
    }
}

class GenerateBinaryTree
{
    public $root;

    public function __construct()
    {
        $this->root = NULL;
    }

    public function create($tmp)
    {
        if ($this->root == NULL) {
            $this->root = new NodeOfTree($tmp);
        }
        else
        {

            $current = $this->root;
            while (true)
            {
                if ($tmp < $current->tmp)
                {

                    if ($current->left)
                    {
                        $current = $current->left;
                    }
                    else
                        {
                            $current->left = new NodeOfTree($tmp);
                            break;
                        }
                } else if ($tmp > $current->tmp)
                {
                    if ($current->right)
                    {
                        $current = $current->right;
                    }
                    else
                    {
                        $current->right = new NodeOfTree($tmp);
                        break;
                    }
                }
                else
                {
                    break;
                }
            }
        }
    }
}

$arr = [2, 3, 4, 7, 1, 4, 7, 4, 2, 5, 7, 9, 3, 2, 5, 7];

$tree = new GenerateBinaryTree();

for ($i = 0, $n = count($arr); $i < $n; $i++)
{
    $tree->create($arr[$i]);
}
echo 'Array = [ ' . join(', ',$arr) . ' ];';

echo '<pre>';
var_dump($tree);