refactoring (use methods)

Author: dan-on

src/IntervalTree.php

@@ -180,32 +180,31 @@ private function insertFixup(Node $insertNode): void
                     $currentNode->getParent()->setColor(NodeColor::black());
                     $uncleNode->setColor(NodeColor::black());
                     $grandfather->setColor(NodeColor::red());
-                    $currentNode = $currentNode->getParent()->getParent();
+                    $currentNode = $grandfather;
                 } else {
                     if ($currentNode === $currentNode->getParent()->getRight()) {
                         $currentNode = $currentNode->getParent();
                         $this->rotateLeft($currentNode);
                     }
                     $currentNode->getParent()->setColor(NodeColor::black());
                     $grandfather->setColor(NodeColor::red());
-                    $this->rotateRight($currentNode->getParent()->getParent());
+                    $this->rotateRight($grandfather);
                 }
             } else {
-                $grandfather = $currentNode->getParent()->getParent();
                 $uncleNode = $grandfather->getLeft();
                 if ($uncleNode->getColor()->isRed()) {
                     $currentNode->getParent()->setColor(NodeColor::black());
                     $uncleNode->setColor(NodeColor::black());
                     $grandfather->setColor(NodeColor::red());
-                    $currentNode = $currentNode->getParent()->getParent();
+                    $currentNode = $grandfather;
                 } else {
                     if ($currentNode === $currentNode->getParent()->getLeft()) {
                         $currentNode = $currentNode->getParent();
                         $this->rotateRight($currentNode);
                     }
                     $currentNode->getParent()->setColor(NodeColor::black());
                     $grandfather->setColor(NodeColor::red());
-                    $this->rotateLeft($currentNode->getParent()->getParent());
+                    $this->rotateLeft($grandfather);
                 }
             }
         }
@@ -385,7 +384,6 @@ private function treeSuccessor(Node $node): ?Node
     private function rotateLeft(Node $x): void
     {
         $y = $x->getRight();
-
         $x->setRight($y->getLeft()); // b goes to x.right
 
         if ($y->getLeft() !== $this->nilNode) {
@@ -449,7 +447,10 @@ private function rotateRight(Node $y): void
      */
     private function treeWalk(): Iterator
     {
-        $stack = [$this->root];
+        if ($this->root !== null) {
+            $stack = [$this->root];
+            yield $this->root;
+        }
         while (!empty($stack)) {
             $node = array_pop($stack);
             if ($node->getLeft() !== $this->nilNode) {

src/Node.php

@@ -126,27 +126,23 @@ public function copyPairFrom(Node $otherNode): void
     public function updateMax(): void
     {
         $this->max = $this->getPair()->getInterval();
-
         if ($this->getRight()->max !== null) {
             $this->max = $this->max->merge($this->getRight()->max);
         }
-        if ($this->left->max !== null) {
+        if ($this->getLeft()->max !== null) {
             $this->max = $this->max->merge($this->getLeft()->max);
         }
     }
 
-    // Other_node does not intersect any node of left subtree, if this.left.max < other_node.item.key.low
     public function notIntersectLeftSubtree(Node $searchNode): bool
     {
         $high = $this->getLeft()->max->getHigh() ?? $this->getLeft()->getPair()->getInterval()->getHigh();
         return $high < $searchNode->getPair()->getInterval()->getLow();
     }
 
-    // Other_node does not intersect right subtree if other_node.item.key.high < this.right.key.low
     public function notIntersectRightSubtree(Node $searchNode): bool
     {
-        //const comparable_less_than = this.item.key.constructor.comparable_less_than;  // static method
-        $low = $this->right->max->getLow() ?? $this->getRight()->getPair()->getInterval()->getLow();
+        $low = $this->getRight()->max->getLow() ?? $this->getRight()->getPair()->getInterval()->getLow();
         return $searchNode->getPair()->getInterval()->getHigh() < $low;
     }
 }