/**
* @param $mode
* @return array
*/
public function depthFirst($mode)
{
/**
* @var BinaryTreeNode $root
*/
$root = $this->getRoot();
// uses a Stack
$resultArray = [];
$stack = new Stack();
switch ($mode) {
case self::SEARCH_PRE_ORDER:
/*current + left + right */
$current = $root;
$stack->push($current);
array_push($resultArray, $current->getData());
while (!$stack->isEmpty()) {
if ($current->getLeft() !== null and !in_array($current->getLeft()->getData(), $resultArray)) {
$current = $current->getLeft();
$stack->push($current);
array_push($resultArray, $current->getData());
} elseif ($current->getRight() !== null and !in_array($current->getRight()->getData(), $resultArray)) {
$current = $current->getRight();
$stack->push($current);
array_push($resultArray, $current->getData());
} else {
$stack->pop();
$current = $current->getParent();
}
}
break;
case self::SEARCH_IN_ORDER:
/*left + current + right */
$current = $root;
$stack->push($current);
while (!$stack->isEmpty()) {
if ($current->getLeft() !== null and !in_array($current->getLeft()->getData(), $resultArray)) {
$current = $current->getLeft();
$stack->push($current);
} elseif ($current->getRight() !== null and !in_array($current->getRight()->getData(), $resultArray)) {
array_push($resultArray, $current->getData());
$current = $current->getRight();
$stack->push($current);
} else {
if (!in_array($current->getData(), $resultArray)) {
array_push($resultArray, $current->getData());
}
$stack->pop();
$current = $current->getParent();
}
}
break;
case self::SEARCH_POST_ORDER:
/*left + right + current */
$current = $root;
$stack->push($current);
while (!$stack->isEmpty()) {
if ($current->getLeft() !== null and !in_array($current->getLeft()->getData(), $resultArray)) {
$current = $current->getLeft();
$stack->push($current);
} elseif ($current->getRight() !== null and !in_array($current->getRight()->getData(), $resultArray)) {
$current = $current->getRight();
$stack->push($current);
} else {
if (!in_array($current->getData(), $resultArray)) {
array_push($resultArray, $current->getData());
}
$stack->pop();
$current = $current->getParent();
}
}
break;
}
return $resultArray;
}
public function testPeek()
{
$data = $this->generateData();
$this->stack->push($data);
self::assertEquals($data, $this->stack->peek());
}