/**
* @param DoubleLinkedList $list
* @return DoubleLinkedList
*/
public function quickSort(DoubleLinkedList $list)
{
$listToReturn = new DoubleLinkedList();
$smallerList = new DoubleLinkedList();
$biggerList = new DoubleLinkedList();
$current = $list->getBottom();
if (!$current) {
return $listToReturn;
}
$pivot = $current->getData();
$listToReturn->add($pivot);
while ($current) {
if ($current->getData() < $pivot) {
$smallerList->add($current->getData());
} elseif ($current->getData() > $pivot) {
$biggerList->add($current->getData());
}
$current = $current->getNext();
}
$sortedFirst = $this->quickSort($smallerList);
$sortedSecond = $this->quickSort($biggerList);
$listToReturn = $this->append($sortedFirst, $listToReturn);
$listToReturn = $this->append($listToReturn, $sortedSecond);
return $listToReturn;
}
