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<?php |
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declare(strict_types=1); |
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/* |
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* Copyright (C) 2019 Sebastian Böttger <[email protected]> |
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* You may use, distribute and modify this code under the |
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* terms of the MIT license. |
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* |
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* You should have received a copy of the MIT license with |
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* this file. If not, please visit: https://opensource.org/licenses/mit-license.php |
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*/ |
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namespace Seboettg\Forest; |
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use Seboettg\Forest\BinaryTree\BinaryNode; |
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use Seboettg\Forest\BinaryTree\BinaryNodeInterface; |
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use Seboettg\Forest\BinaryTree\BinaryTreeInterface; |
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use Seboettg\Forest\Item\ItemInterface; |
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use Seboettg\Forest\General\TreeTraversalTrait; |
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/** |
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* Class BinaryTree |
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* A binary tree is a recursive data structure where each node can have 2 children at most. |
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* |
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* @package Seboettg\Forest |
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*/ |
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class BinaryTree implements BinaryTree\BinaryTreeInterface |
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{ |
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use TreeTraversalTrait; |
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/** |
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* @var BinaryNodeInterface |
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*/ |
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protected $root; |
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/** |
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* @var int |
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*/ |
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protected $elementCount = 0; |
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protected $itemType; |
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public function __construct(?string $itemType = null) |
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{ |
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$this->itemType = $itemType; |
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} |
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/** |
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* @param ItemInterface $value |
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* |
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* @return BinaryNodeInterface |
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*/ |
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final public function search(ItemInterface $value): ?BinaryNodeInterface |
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{ |
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return $this->searchRecursive($value, $this->root); |
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} |
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/** |
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* @param ItemInterface $value |
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* @param BinaryNodeInterface $node |
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* @return BinaryNodeInterface |
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*/ |
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final protected function searchRecursive(ItemInterface $value, BinaryNodeInterface $node = null): ?BinaryNodeInterface |
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{ |
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if ($node === null) { |
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return null; |
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} else if ($node->getItem()->compareTo($value) === 0) { |
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return $node; |
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} else if ($node->getItem()->compareTo($value) > 0) { |
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return $this->searchRecursive($value, $node->getLeft()); |
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} else { |
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return $this->searchRecursive($value, $node->getRight()); |
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} |
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} |
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/** |
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* @param mixed $value |
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* @return BinaryTree |
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*/ |
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public function insert($value): BinaryTreeInterface |
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{ |
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++$this->elementCount; |
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if (!empty($this->itemType) && is_object($value) && get_class($value) === $this->itemType) { |
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$this->insertItem($value); |
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} else { |
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if (empty($this->itemType)) { |
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$this->insertItem($value); |
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} else { |
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$item = new $this->itemType($value); |
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$this->insertItem($item); |
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} |
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} |
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return $this; |
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} |
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public function remove($value): BinaryTreeInterface |
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{ |
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if (!empty($this->itemType) && is_object($value) && get_class($value) === $this->itemType) { |
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$this->removeItem($value); |
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} else { |
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if (empty($this->itemType)) { |
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$this->removeItem($value); |
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} else { |
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$item = new $this->itemType($value); |
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$this->removeItem($item); |
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} |
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} |
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--$this->elementCount; |
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return $this; |
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} |
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/** |
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* @param $value |
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*/ |
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protected function insertItem($value): void |
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{ |
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if ($this->root === null) { |
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$this->root = new BinaryNode($value); |
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} else { |
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$this->insertRecursive($this->root, $value); |
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} |
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} |
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/** |
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* @param BinaryNodeInterface $node |
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* @param ItemInterface $value |
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* @return void |
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*/ |
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final private function insertRecursive(BinaryNodeInterface $node, ItemInterface $value): void |
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{ |
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if ($node->getItem()->compareTo($value) >= 0) { |
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if ($node->getLeft() === null) { |
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$node->setLeft(new BinaryNode($value)); |
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} else { |
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$this->insertRecursive($node->getLeft(), $value); |
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} |
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} else { |
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if ($node->getRight() === null) { |
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$node->setRight(new BinaryNode($value)); |
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} else { |
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$this->insertRecursive($node->getRight(), $value); |
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} |
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} |
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} |
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/** |
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* @return int number of nodes in the tree |
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*/ |
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final public function count(): int |
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{ |
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return $this->elementCount; |
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} |
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/** |
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* @return int height of the tree |
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*/ |
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final public function getHeight(): int |
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{ |
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return $this->root->getHeight(); |
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} |
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/** |
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* @return BinaryNodeInterface |
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*/ |
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final public function getRootNode() |
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{ |
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return $this->root; |
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} |
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/** |
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* @param BinaryNodeInterface $node |
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* @return BinaryNodeInterface |
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*/ |
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protected function getLeftMostLeaf(BinaryNodeInterface $node): BinaryNodeInterface |
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{ |
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$current = $node; |
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while (null !== $current->getLeft()) { |
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$current = $current->getLeft(); |
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} |
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return $current; |
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} |
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/** |
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* @param ItemInterface $item |
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*/ |
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protected function removeItem(ItemInterface $item): void |
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{ |
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if ($this->root->getItem()->compareTo($item) !== 0) { |
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$this->removeItemRecursive($item, $this->root); |
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return; |
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} |
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$this->reassignSubtree($this->root); |
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} |
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/** |
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* @param ItemInterface $item |
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* @param BinaryNodeInterface|null $node |
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*/ |
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protected function removeItemRecursive(ItemInterface $item, ?BinaryNodeInterface &$node = null): void |
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{ |
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$tmp = $node; |
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$cmp = $node->getItem()->compareTo($item); |
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$child = null; |
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switch($cmp) { |
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case -1: |
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$child = $node->getRight(); |
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break; |
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case 0: |
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return; |
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case 1: |
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$child = $node->getLeft(); |
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} |
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if ($child->getItem()->compareTo($item) !== 0) { |
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$this->removeItemRecursive($item, $child); |
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} else { |
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$this->reassignSubtree($child); |
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($cmp > 0) ? $tmp->setLeft($child) : $tmp->setRight($child); |
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$node = $tmp; |
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} |
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} |
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/** |
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* @param BinaryNodeInterface $node |
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*/ |
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protected function reassignSubtree(BinaryNodeInterface &$node): void |
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{ |
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if (empty($node->getLeft()) && empty($node->getRight())) { //no children? |
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$node = null; // just unset the node and return |
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return; |
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} |
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if (empty($node->getRight())) { // is there something on the right? |
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$tmp = $node->getLeft(); // if not, return left node |
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$tmp->setParent(null); |
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$node = $tmp; |
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} else { |
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if (empty($node->getLeft())) { // is there something on the left? |
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$tmp = $node->getRight(); // if not, return right node |
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$tmp->setParent(null); |
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$node = $tmp; |
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} else { // left and right? |
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$tmp = $node->getRight(); //keep right in mind |
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$leftMostLeaf = $this->getLeftMostLeaf($tmp); // get the leftmost leaf of the right subtree |
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$leftMostLeaf->setLeft($node->getLeft()); // append the left subtree to the leftmost leaf of the right subtree |
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$node = $tmp; |
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} |
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} |
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} |
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} |
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This check looks for calls to methods that do not seem to exist on a given type. It looks for the method on the type itself as well as in inherited classes or implemented interfaces.
This is most likely a typographical error or the method has been renamed.