class BinarySearchTree<T:Comparable> {private(set) var value:Tprivate(set) var parent:BinarySearchTree?private(set) var leftChild:BinarySearchTree?private(set) var rightChild:BinarySearchTree?public init(value: T) {self.value = value}public convenience init(array: [T]) {// 將數組的第一個值賦給root，數組其他的值直接插入到binarySearchTree中// precondition use as assertprecondition(array.count > 0)self.init(value: array.first!)// array.dropFirst()// A subsequence starting after the first element of the sequence.for value in array.dropFirst() {insert(value: value)}}public var isRoot: Bool {return parent == nil}public var isLeftChild: Bool {return parent?.leftChild === self}public var isRightChild: Bool {return parent?.rightChild === self}public var isChild: Bool {return isLeftChild || isRightChild}public var hasLeftChild: Bool {return leftChild != nil}public var hasRightChild: Bool {return rightChild != nil}public var isLeaf: Bool {return (leftChild == nil) && (rightChild == nil)}public var hasAnyChild: Bool {return hasLeftChild || hasRightChild}public var count: Int {return (leftChild?.count ?? 0) + 1 + (rightChild?.count ?? 0)}public func insert(value: T) {if value == self.value {return}if value < self.value {if let left = self.leftChild {left.insert(value: value)} else {self.leftChild = BinarySearchTree(value: value)self.leftChild?.parent = self}} else {if let right = self.rightChild {right.insert(value: value)} else {self.rightChild = BinarySearchTree(value: value)self.rightChild?.parent = self}}}public func search(value: T) -> BinarySearchTree? {if value < self.value {return self.leftChild?.search(value: value)} else if value > self.value {return self.rightChild?.search(value: value)} else {return self}}public func traverseInOrder(process: (T) -> Void) {leftChild?.traverseInOrder(process: process)process(value)rightChild?.traverseInOrder(process: process)}public func traversePreOrder(process: (T) -> Void) {process(value)leftChild?.traversePreOrder(process: process)rightChild?.traversePreOrder(process: process)}public func traversePostOrder(process: (T) -> Void) {leftChild?.traversePostOrder(process: process)rightChild?.traversePostOrder(process: process)process(value)}public func minValue() -> BinarySearchTree {var node = selfwhile let next = node.leftChild {node = next}return node}public func maxValue() -> BinarySearchTree {var node = selfwhile let next = node.rightChild {node = next}return node}// height高度是當前節點到葉子結點的最大距離public func height() -> Int {if isLeaf {return 0} else {return 1 + max(self.leftChild?.height() ?? 0, self.rightChild?.height() ?? 0 )}}// depth 深度是當前到根結點的距離public func depth() -> Int {var node = selfvar edges = 0while let parent = node.parent {node = parentedges += 1}return edges}// precede the current value in sorted orderpublic func predecessor() -> BinarySearchTree<T>? {if let left = self.leftChild {return left.maxValue()} else {var node = selfwhile let parent = node.parent {if node.isRightChild {return parent} else {node = parent}}}return nil}public func successor() -> BinarySearchTree<T>? {if let right = self.rightChild {return right.minValue()} else {var node = selfwhile let parent = node.parent {if node.isLeftChild {return parent} else {node = parent}}}return nil}

?　　//判斷插入一個值后當前是否還是BST

? ? public func isBST(min:T, max:T) -> Bool {

? ? ? ? if value < min || value > max {

? ? ? ? ? ? return false

? ? ? ? }

? ? ? ? let leftBST = self.leftChild?.isBST(min: min, max: value) ?? true

? ? ? ? let rightBST = self.rightChild?.isBST(min: value, max: max) ?? true

?? ? ? ?

? ? ? ? return leftBST && rightBST

? ? }

private func reconnectParentToNode(node: BinarySearchTree?) {if let parent = self.parent {if isLeftChild {parent.leftChild = node} else {parent.rightChild = node}}node?.parent = self.parent} }extension BinarySearchTree:CustomStringConvertible {var description: String {var text = "\(value): {"if leftChild != nil {text += "{ left: " + (leftChild?.description)! + "}"}if rightChild != nil {text += "{ right: " + (rightChild?.description)! + "}"}text += "}"return text} }

測試：

let bst = BinarySearchTree<Int>(value: 5) bst.insert(value: 3) bst.insert(value: 8) bst.insert(value: 1) bst.insert(value: 9) bst.insert(value: 4) print(bst)let bstTwo = BinarySearchTree<Int>(array: [5, 3, 8, 1, 9, 4]) print(bstTwo)bstTwo.search(value: 1) bstTwo.search(value: 6)print("PreOrder") bstTwo.traversePreOrder{value in print(value)} print("InOrder") bstTwo.traverseInOrder{value in print(value)} print("PostOrder") bstTwo.traversePostOrder{value in print(value)}bstTwo.minValue() bstTwo.maxValue()bstTwo.height()bstTwo.search(value: 9)?.depth() bstTwo.search(value: 8)?.predecessor() bstTwo.search(value: 4)?.successor()

bstTwo.search(value: 4)?.insert(value: 10)

bstTwo.isBST(min: Int.min, max: Int.max) ?// false

?

轉載于:https://www.cnblogs.com/HackHer/p/8529540.html

超強干貨來襲 云風專訪：近40年碼齡，通宵達旦的技術人生

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