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Commit 54f18c8

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authored
Merge pull request #6 from AryanAhadinia/issue_5
Implement Red-Black Tree
2 parents 2146851 + 0063f6f commit 54f18c8

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3 files changed

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import Foundation
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class RedBlackTreeNode<T: Comparable> {
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var value: T
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var isRed: Bool
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var left: RedBlackTreeNode?
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var right: RedBlackTreeNode?
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init(value: T, isRed: Bool, left: RedBlackTreeNode?, right: RedBlackTreeNode?) {
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self.value = value
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self.isRed = isRed
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self.left = left
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self.right = right
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}
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static func isRedNode(node: RedBlackTreeNode?) -> Bool {
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if (node == nil) {
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return false
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}
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return node!.isRed
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}
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func clockwiseRotate() -> RedBlackTreeNode {
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let t = self.left!
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self.left = t.right
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t.right = self
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t.isRed = RedBlackTreeNode.isRedNode(node: t.right)
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t.right!.isRed = true
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return t
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}
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func counterclockwiseRotate() -> RedBlackTreeNode {
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let t = self.right!
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self.right = t.left
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t.left = self
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t.isRed = RedBlackTreeNode.isRedNode(node: t.left)
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t.left!.isRed = true
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return t
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}
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func flip() {
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self.isRed = !self.isRed
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}
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func exchange() {
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self.flip()
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self.left?.flip()
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self.right?.flip()
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}
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func minimum() -> RedBlackTreeNode {
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if (self.left == nil) {
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return self
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}
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return self.left!.minimum()
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}
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func maximum() -> RedBlackTreeNode {
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if (self.right == nil) {
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return self
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}
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return self.right!.maximum()
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}
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func bubbleUp() -> RedBlackTreeNode {
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var t = self
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if (RedBlackTreeNode.isRedNode(node: t.right)) {
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t = t.counterclockwiseRotate()
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}
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if (RedBlackTreeNode.isRedNode(node: t.left) && RedBlackTreeNode.isRedNode(node: t.left!.left)) {
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t = t.clockwiseRotate()
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}
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if (RedBlackTreeNode.isRedNode(node: t.left) && RedBlackTreeNode.isRedNode(node: t.right)) {
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t.exchange()
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}
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return t
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}
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func alignLeftNode() -> RedBlackTreeNode {
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var t = self
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t.exchange()
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if (self.right != nil && RedBlackTreeNode.isRedNode(node: t.right!.left)) {
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t.right = t.right!.clockwiseRotate()
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t = t.counterclockwiseRotate()
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t.exchange()
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}
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return t
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}
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func alignRightNode() -> RedBlackTreeNode {
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var t = self
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t.exchange()
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if (self.left != nil && RedBlackTreeNode.isRedNode(node: t.left!.left)) {
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t = t.clockwiseRotate()
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t.exchange()
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}
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return t
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}
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func search(value: T) -> RedBlackTreeNode? {
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if (self.value == value) {
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return self
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} else if (self.value < value) {
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return self.left?.search(value: value)
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} else {
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return self.right?.search(value: value)
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}
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}
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func removeMinimum() -> RedBlackTreeNode? {
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if (self.left == nil) {
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return nil
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}
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var t = self
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if (!RedBlackTreeNode.isRedNode(node: t.left) && !RedBlackTreeNode.isRedNode(node: t.left!.left)) {
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t = t.alignLeftNode()
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}
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t.left = t.left!.removeMinimum()
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return t.bubbleUp()
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}
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func preorderTraversal() -> Array<T> {
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var traversal: Array<T> = [self.value]
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if (self.left != nil) {
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traversal += left!.inorderTraversal()
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}
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if (self.right != nil) {
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traversal += right!.inorderTraversal()
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}
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return traversal;
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}
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func inorderTraversal() -> Array<T> {
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var traversal: Array<T> = []
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if (self.left != nil) {
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traversal += left!.inorderTraversal()
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}
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traversal += [self.value]
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if (self.right != nil) {
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traversal += right!.inorderTraversal()
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}
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return traversal;
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}
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func postorderTraversal() -> Array<T> {
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var traversal: Array<T> = []
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if (self.left != nil) {
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traversal += left!.inorderTraversal()
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}
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if (self.right != nil) {
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traversal += right!.inorderTraversal()
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}
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traversal += [self.value]
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return traversal;
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}
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}
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class RedBlackTree<T: Comparable> {
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var root: RedBlackTreeNode<T>? = nil
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static func insert(inRoot: RedBlackTreeNode<T>?, val: T) -> RedBlackTreeNode<T>? {
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var root = inRoot
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if (root == nil) {
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return RedBlackTreeNode(value: val, isRed: true, left: nil, right: nil)
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}
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if (RedBlackTreeNode.isRedNode(node: root!.left) && RedBlackTreeNode.isRedNode(node: root!.right)) {
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root!.exchange()
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}
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if (val == root!.value) {
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root!.value = val
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} else if (val < root!.value) {
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root!.left = insert(inRoot: root!.left, val: val)
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} else {
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root!.right = insert(inRoot: root!.right, val: val)
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}
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if (RedBlackTreeNode.isRedNode(node: root!.right)) {
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root = root!.counterclockwiseRotate()
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}
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if (RedBlackTreeNode.isRedNode(node: root!.left) && RedBlackTreeNode.isRedNode(node: root!.left!.left)) {
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root = root!.clockwiseRotate()
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}
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if (RedBlackTreeNode.isRedNode(node: root!.left) && RedBlackTreeNode.isRedNode(node: root!.right)) {
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root!.exchange();
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}
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return root;
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}
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static func remove(inRoot: RedBlackTreeNode<T>?, val: T) -> RedBlackTreeNode<T>? {
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var root = inRoot;
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if (val < root!.value) {
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if (root!.left != nil && !(RedBlackTreeNode.isRedNode(node: root!.left)) && !(RedBlackTreeNode.isRedNode(node: root!.left!.left))) {
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root = root!.alignLeftNode()
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}
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root!.left = remove(inRoot: root!.left, val: val);
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} else {
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if (RedBlackTreeNode.isRedNode(node: root!.left)) {
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root = root!.clockwiseRotate()
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}
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if (val == root!.value && root!.right == nil) {
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return nil
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}
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if (root!.right != nil && !(RedBlackTreeNode.isRedNode(node: root!.right)) && !(RedBlackTreeNode.isRedNode(node: root!.right!.left))) {
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root = root!.alignRightNode()
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}
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if (val == root!.value) {
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root!.value = root!.right!.minimum().value
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root!.right = root!.right!.removeMinimum()
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} else {
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root!.right = remove(inRoot: root!.right, val: val);
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}
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}
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return root!.bubbleUp()
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}
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func insert(value: T) {
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root = RedBlackTree.insert(inRoot: root, val: value)
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if (root != nil) {
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root!.isRed = false
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}
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}
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func remove(value: T) {
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if (search(value: value) == nil) {
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return
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}
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root = RedBlackTree.remove(inRoot: root, val: value)
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if (root != nil) {
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root!.isRed = false
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}
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}
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func search(value: T) -> RedBlackTreeNode<T>? {
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return root?.search(value: value)
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}
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func preorderTraversal() -> Array<T> {
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if (root == nil) {
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return Array<T>()
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}
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return root!.preorderTraversal()
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}
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func inorderTraversal() -> Array<T> {
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if (root == nil) {
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return Array<T>()
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}
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return root!.inorderTraversal()
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}
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func postorderTraversal() -> Array<T> {
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if (root == nil) {
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return Array<T>()
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}
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return root!.postorderTraversal()
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}
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}

‎Data Structures.playground/Pages/Red-Black Tree.xcplaygroundpage/Contents.swift‎

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This file was deleted.

‎README.md‎

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# swift-algorithms-data-structs [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38d29fed78fa85652e3a63e154dd8e8829/media/badge.svg)](https://github.com/sindresorhus/awesome)
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3-
[![Language](https://img.shields.io/badge/language-Swift_5.0-orange.svg)]()
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[![Language](https://img.shields.io/badge/language-Swift_5.3-orange.svg)]()
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[![License](https://img.shields.io/badge/license-MIT-blue.svg)]()
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**Last Update: 27/April/2019.**
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**Last Update: 18/July/2021.**
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![](https://github.com/jVirus/swift-algorithms-data-structs/blob/master/cover-algo-datastruct.png)
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