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Merge pull request #2 from dan-on/deep-nesting-problem-fix
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Fix deep nesting problem
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@dan-on
dan-on committed Oct 23, 2020
2 parents 41c3e3b + c0b3b21 commit daa785b
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Showing 2 changed files with 72 additions and 60 deletions.
112 changes: 56 additions & 56 deletions src/IntervalTree.php
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Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ public function getItems()
*/
public function isEmpty()
{
return ($this->root == null || $this->root == $this->nilNode);
return ($this->root === null || $this->root === $this->nilNode);
}

/**
Expand Down Expand Up @@ -196,7 +196,7 @@ public function map($callback)
public function recalcMax($node)
{
$nodeCurrent = $node;
while ($nodeCurrent->parent != null) {
while ($nodeCurrent->parent !== null) {
$nodeCurrent->parent->updateMax();
$nodeCurrent = $nodeCurrent->parent;
}
Expand All @@ -207,10 +207,10 @@ public function treeInsert($insertNode)
$currentNode = $this->root;
$parentNode = null;

if ($this->root == null || $this->root == $this->nilNode) {
if ($this->root === null || $this->root === $this->nilNode) {
$this->root = $insertNode;
} else {
while ($currentNode != $this->nilNode) {
while ($currentNode !== $this->nilNode) {
$parentNode = $currentNode;
if ($insertNode->lessThan($currentNode)) {
$currentNode = $currentNode->left;
Expand All @@ -235,21 +235,21 @@ public function treeInsert($insertNode)
// Go upwords to the root and re-color until violation will be resolved
public function insertFixup($insertNode)
{
$currentNode;
$uncleNode;
$currentNode = null;
$uncleNode = null;

$currentNode = $insertNode;
while ($currentNode != $this->root && $currentNode->parent->color == Node::COLOR_RED) {
if ($currentNode->parent == $currentNode->parent->parent->left) { // parent is left child of grandfather
while ($currentNode !== $this->root && $currentNode->parent->color === Node::COLOR_RED) {
if ($currentNode->parent === $currentNode->parent->parent->left) { // parent is left child of grandfather
$uncleNode = $currentNode->parent->parent->right; // right brother of parent
if ($uncleNode->color == Node::COLOR_RED) { // Case 1. Uncle is red
if ($uncleNode->color === Node::COLOR_RED) { // Case 1. Uncle is red
// re-color father and uncle into black
$currentNode->parent->color = Node::COLOR_BLACK;
$uncleNode->color = Node::COLOR_BLACK;
$currentNode->parent->parent->color = Node::COLOR_RED;
$currentNode = $currentNode->parent->parent;
} else { // Case 2 & 3. Uncle is black
if ($currentNode == $currentNode->parent->right) { // Case 2. Current if right child
if ($currentNode === $currentNode->parent->right) { // Case 2. Current if right child
// This case is transformed into Case 3.
$currentNode = $currentNode->parent;
$this->rotateLeft($currentNode);
Expand All @@ -261,14 +261,14 @@ public function insertFixup($insertNode)
}
} else { // parent is right child of grandfather
$uncleNode = $currentNode->parent->parent->left; // left brother of parent
if ($uncleNode->color == Node::COLOR_RED) { // Case 4. Uncle is red
if ($uncleNode->color === Node::COLOR_RED) { // Case 4. Uncle is red
// re-color father and uncle into black
$currentNode->parent->color = Node::COLOR_BLACK;
$uncleNode->color = Node::COLOR_BLACK;
$currentNode->parent->parent->color = Node::COLOR_RED;
$currentNode = $currentNode->parent->parent;
} else {
if ($currentNode == $currentNode->parent->left) { // Case 5. Current is left child
if ($currentNode === $currentNode->parent->left) { // Case 5. Current is left child
// Transform into case 6
$currentNode = $currentNode->parent;
$this->rotateRight($currentNode);
Expand All @@ -289,28 +289,28 @@ public function treeDelete($deleteNode)
$cutNode; // node to be cut - either delete_node or successor_node ("y" from 14.4)
$fixNode; // node to fix rb tree property ("x" from 14.4)

if ($deleteNode->left == $this->nilNode || $deleteNode->right == $this->nilNode) { // delete_node has less then 2 children
if ($deleteNode->left === $this->nilNode || $deleteNode->right === $this->nilNode) { // delete_node has less then 2 children
$cutNode = $deleteNode;
} else { // delete_node has 2 children
$cutNode = $this->treeSuccessor($deleteNode);
}

// fix_node if single child of cut_node
if ($cutNode->left != $this->nilNode) {
if ($cutNode->left !== $this->nilNode) {
$fixNode = $cutNode->left;
} else {
$fixNode = $cutNode->right;
}

// remove cut_node from parent
/*if (fix_node != this.nil_node) {*/
/*if (fix_node !== this.nil_node) {*/
$fixNode->parent = $cutNode->parent;
/*}*/

if ($cutNode == $this->root) {
if ($cutNode === $this->root) {
$this->root = $fixNode;
} else {
if ($cutNode == $cutNode->parent->left) {
if ($cutNode === $cutNode->parent->left) {
$cutNode->parent->left = $fixNode;
} else {
$cutNode->parent->right = $fixNode;
Expand All @@ -323,13 +323,13 @@ public function treeDelete($deleteNode)
// COPY DATA !!!
// Delete_node becomes cut_node, it means that we cannot hold reference
// to node in outer structure and we will have to delete by key, additional search need
if ($cutNode != $deleteNode) {
if ($cutNode !== $deleteNode) {
$deleteNode->copyData($cutNode);
$deleteNode->updateMax(); // update max property of the cut node at the new place
$this->recalcMax($deleteNode); // update max property upward from delete_node to root
}

if ( /*fix_node != this.nil_node && */$cutNode->color == Node::COLOR_BLACK) {
if ( /*fix_node !== this.nil_node && */$cutNode->color === Node::COLOR_BLACK) {
$this->deleteFixup($fixNode);
}
}
Expand All @@ -339,22 +339,22 @@ public function deleteFixup($fixNode)
$currentNode = $fixNode;
$brotherNode;

while ($currentNode != $this->root && $currentNode->parent != null && $currentNode->color == Node::COLOR_BLACK) {
if ($currentNode == $currentNode->parent->left) { // fix node is left child
while ($currentNode !== $this->root && $currentNode->parent !== null && $currentNode->color === Node::COLOR_BLACK) {
if ($currentNode === $currentNode->parent->left) { // fix node is left child
$brotherNode = $currentNode->parent->right;
if ($brotherNode->color == Node::COLOR_RED) { // Case 1. Brother is red
if ($brotherNode->color === Node::COLOR_RED) { // Case 1. Brother is red
$brotherNode->color = Node::COLOR_BLACK; // re-color brother
$currentNode->parent->color = Node::COLOR_RED; // re-color father
$this->rotateLeft($currentNode->parent);
$brotherNode = $currentNode->parent->right; // update brother
}
// Derive to cases 2..4: brother is black
if ($brotherNode->left->color == Node::COLOR_BLACK &&
$brotherNode->right->color == Node::COLOR_BLACK) { // case 2: both nephews black
if ($brotherNode->left->color === Node::COLOR_BLACK &&
$brotherNode->right->color === Node::COLOR_BLACK) { // case 2: both nephews black
$brotherNode->color = Node::COLOR_RED; // re-color brother
$currentNode = $currentNode->parent; // continue iteration
} else {
if ($brotherNode->right->color == Node::COLOR_BLACK) { // case 3: left nephew red, right nephew black
if ($brotherNode->right->color === Node::COLOR_BLACK) { // case 3: left nephew red, right nephew black
$brotherNode->color = Node::COLOR_RED; // re-color brother
$brotherNode->left->color = Node::COLOR_BLACK; // re-color nephew
$this->rotateRight($brotherNode);
Expand All @@ -370,19 +370,19 @@ public function deleteFixup($fixNode)
}
} else { // fix node is right child
$brotherNode = $currentNode->parent->left;
if ($brotherNode->color == Node::COLOR_RED) { // Case 1. Brother is red
if ($brotherNode->color === Node::COLOR_RED) { // Case 1. Brother is red
$brotherNode->color = Node::COLOR_BLACK; // re-color brother
$currentNode->parent->color = Node::COLOR_RED; // re-color father
$this->rotateRight($currentNode->parent);
$brotherNode = $currentNode->parent->left; // update brother
}
// Go to cases 2..4
if ($brotherNode->left->color == Node::COLOR_BLACK &&
$brotherNode->right->color == Node::COLOR_BLACK) { // case 2
if ($brotherNode->left->color === Node::COLOR_BLACK &&
$brotherNode->right->color === Node::COLOR_BLACK) { // case 2
$brotherNode->color = Node::COLOR_RED; // re-color brother
$currentNode = $currentNode->parent; // continue iteration
} else {
if ($brotherNode->left->color == Node::COLOR_BLACK) { // case 3: right nephew red, left nephew black
if ($brotherNode->left->color === Node::COLOR_BLACK) { // case 3: right nephew red, left nephew black
$brotherNode->color = Node::COLOR_RED; // re-color brother
$brotherNode->right->color = Node::COLOR_BLACK; // re-color nephew
$this->rotateLeft($brotherNode);
Expand All @@ -404,7 +404,7 @@ public function deleteFixup($fixNode)

public function treeSearch($node, $searchNode)
{
if ($node == null || $node == $this->nilNode) {
if ($node === null || $node === $this->nilNode) {
return null;
}

Expand All @@ -422,18 +422,18 @@ public function treeSearch($node, $searchNode)
// Search all intervals intersecting given one
public function treeSearchInterval($node, $searchNode, &$res = [])
{
if ($node != null && $node != $this->nilNode) {
// if (node->left != this.nil_node && node->left->max >= low) {
if ($node->left != $this->nilNode && !$node->notIntersectLeftSubtree($searchNode)) {
if ($node !== null && $node !== $this->nilNode) {
// if (node->left !== this.nil_node && node->left->max >= low) {
if ($node->left !== $this->nilNode && !$node->notIntersectLeftSubtree($searchNode)) {
yield from $this->treeSearchInterval($node->left, $searchNode, $res);
}
// if (low <= node->high && node->low <= high) {
if ($node->intersect($searchNode)) {
$res[] = $node;
yield $node;
}
// if (node->right != this.nil_node && node->low <= high) {
if ($node->right != $this->nilNode && !$node->notIntersectRightSubtree($searchNode)) {
// if (node->right !== this.nil_node && node->low <= high) {
if ($node->right !== $this->nilNode && !$node->notIntersectRightSubtree($searchNode)) {
yield from $this->treeSearchInterval($node->right, $searchNode, $res);
}
}
Expand All @@ -442,7 +442,7 @@ public function treeSearchInterval($node, $searchNode, &$res = [])
public function localMinimum($node)
{
$nodeMin = $node;
while ($nodeMin->left != null && $nodeMin->left != $this->nilNode) {
while ($nodeMin->left !== null && $nodeMin->left !== $this->nilNode) {
$nodeMin = $nodeMin->left;
}
return $nodeMin;
Expand All @@ -452,7 +452,7 @@ public function localMinimum($node)
public function localMaximum($node)
{
$nodeMax = $node;
while ($nodeMax->right != null && $nodeMax->right != $this->nilNode) {
while ($nodeMax->right !== null && $nodeMax->right !== $this->nilNode) {
$nodeMax = $nodeMax->right;
}
return $nodeMax;
Expand All @@ -464,12 +464,12 @@ public function treeSuccessor($node)
$currentNode;
$parentNode;

if ($node->right != $this->nilNode) {
if ($node->right !== $this->nilNode) {
$nodeSuccessor = $this->localMinimum($node->right);
} else {
$currentNode = $node;
$parentNode = $node->parent;
while ($parentNode != null && $parentNode->right == $currentNode) {
while ($parentNode !== null && $parentNode->right === $currentNode) {
$currentNode = $parentNode;
$parentNode = $parentNode->parent;
}
Expand All @@ -491,15 +491,15 @@ public function rotateLeft($x)

$x->right = $y->left; // b goes to x.right

if ($y->left != $this->nilNode) {
if ($y->left !== $this->nilNode) {
$y->left->parent = $x; // x becomes parent of b
}
$y->parent = $x->parent; // move parent

if ($x == $this->root) {
if ($x === $this->root) {
$this->root = $y; // y becomes root
} else { // y becomes child of x.parent
if ($x == $x->parent->left) {
if ($x === $x->parent->left) {
$x->parent->left = $y;
} else {
$x->parent->right = $y;
Expand All @@ -508,12 +508,12 @@ public function rotateLeft($x)
$y->left = $x; // x becomes left child of y
$x->parent = $y; // and y becomes parent of x

if ($x != null && $x != $this->nilNode) {
if ($x !== null && $x !== $this->nilNode) {
$x->updateMax();
}

$y = $x->parent;
if ($y != null && $y != $this->nilNode) {
if ($y !== null && $y !== $this->nilNode) {
$y->updateMax();
}
}
Expand All @@ -524,15 +524,15 @@ public function rotateRight($y)

$y->left = $x->right; // b goes to y.left

if ($x->right != $this->nilNode) {
if ($x->right !== $this->nilNode) {
$x->right->parent = $y; // y becomes parent of b
}
$x->parent = $y->parent; // move parent

if ($y == $this->root) { // x becomes root
if ($y === $this->root) { // x becomes root
$this->root = $x;
} else { // y becomes child of x.parent
if ($y == $y->parent->left) {
if ($y === $y->parent->left) {
$y->parent->left = $x;
} else {
$y->parent->right = $x;
Expand All @@ -541,19 +541,19 @@ public function rotateRight($y)
$x->right = $y; // y becomes right child of x
$y->parent = $x; // and x becomes parent of y

if ($y != null && $y != $this->nilNode) {
if ($y !== null && $y !== $this->nilNode) {
$y->updateMax();
}

$x = $y->parent;
if ($x != null && $x != $this->nilNode) {
if ($x !== null && $x !== $this->nilNode) {
$y->updateMax();
}
}

public function treeWalk($node, $action)
{
if ($node != null && $node != $this->nilNode) {
if ($node !== null && $node !== $this->nilNode) {
$this->treeWalk($node->left, $action);
// arr.push(node.toArray());
$action($node);
Expand All @@ -566,8 +566,8 @@ public function testRedBlackProperty()
{
$res = true;
$this->treeWalk($this->root, function ($node) use (&$res) {
if ($node->color == Node::COLOR_RED) {
if (!($node->left->color == Node::COLOR_BLACK && $node->right->color == Node::COLOR_BLACK)) {
if ($node->color === Node::COLOR_RED) {
if (!($node->left->color === Node::COLOR_BLACK && $node->right->color === Node::COLOR_BLACK)) {
$res = false;
}
}
Expand All @@ -581,20 +581,20 @@ public function testBlackHeightProperty($node)
$height = 0;
$heightLeft = 0;
$heightRight = 0;
if ($node->color == Node::COLOR_BLACK) {
if ($node->color === Node::COLOR_BLACK) {
$height++;
}
if ($node->left != $this->nilNode) {
if ($node->left !== $this->nilNode) {
$heightLeft = $this->testBlackHeightProperty($node->left);
} else {
$heightLeft = 1;
}
if ($node->right != $this->nilNode) {
if ($node->right !== $this->nilNode) {
$heightRight = $this->testBlackHeightProperty($node->right);
} else {
$heightRight = 1;
}
if ($heightLeft != $heightRight) {
if ($heightLeft !== $heightRight) {
throw new Error('Red-black height property violated');
}
$height += $heightLeft;
Expand Down
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