[PHP] Implement Binary Tree

class Node
{
    public $value, $left, $right;

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

Search:
class BST
{
    public $root;

    public function __construct($value = null)
    {
        if ($value !== null) {
            $this->root = new Node($value);
        }
    }

    public function search($value)
    {
        $node = $this->root;

        while($node) {
            if ($value > $node->value) {
                $node = $node->right;
            } elseif ($value < $node->value) {
                $node = $node->left;
            } else {
                break;
            }
        }

        return $node;
    }
}

Insertion:
public function insert($value)
{
    $node = $this->root;
    if (!$node) {
        return $this->root = new Node($value);
    }

    while($node) {
        if ($value > $node->value) {
            if ($node->right) {
                $node = $node->right;
            } else {
                $node = $node->right = new Node($value);
                break;
            }
        } elseif ($value < $node->value) {
            if ($node->left) {
                $node = $node->left;
            } else {
                $node = $node->left = new Node($value);
                break;
            }
        } else {
            break;
        }
    }
    return $node;
}


Min:
public function min()
{
    if (!$this->root) {
        throw new Exception('Tree root is empty!');
    }

    $node = $this->root;
    return $node->min();
}

public function min()
{
    $node = $this;
    while ($node->left) {
        if (!$node->left) {
            break;
        }
        $node = $node->left;
    }
    return $node;
}

Max:
public function max()
{
    if (!$this->root) {
        throw new Exception('Tree root is empty!');
    }

    $node = $this->root;
    return $node->max();
}

public function max()
{
    $node = $this;
    while ($node->right) {
        if (!$node->right) {
            break;
        }
        $node = $node->right;
    }
    return $node;
}