/**
* Depth-first pre-order (without recursion)
* In this case we have to use a Stack.
*
* @param \DataStructure\BinaryTree\Tree $tree
*/
function depth_first_traversal(Tree $tree)
{
$root = $tree->getRoot();
if ($root === null) {
return;
}
$stack = new Stack();
$stack->push($root);
while (!$stack->isEmpty()) {
$node = $stack->pop();
var_dump($node->value);
if ($node->right !== null) {
$stack->push($node->right);
}
if ($node->left !== null) {
$stack->push($node->left);
}
}
}
/**
* Breadth-first traversal uses a Queue instead od a Stack.
*
* @param \DataStructure\BinaryTree\Tree $tree
*/
function breadth_first_traversal(Tree $tree)
{
$root = $tree->getRoot();
if ($root === null) {
return;
}
$queue = new Queue();
$queue->push($root);
while (!$queue->isEmpty()) {
$node = $queue->pop();
var_dump($node->value);
if ($node->left !== null) {
$queue->push($node->left);
}
if ($node->right !== null) {
$queue->push($node->right);
}
}
}
