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13_二叉搜索树.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
// 封装 二叉搜索树 BST binary search tree
function BinarySearchTree() {
// 属性
this.root = null
this.count = 0
let _this = this
let nodeValue ='' // 搜索时用
// 内部类
function Node(key, value) {
this.key = key
this.value = value
this.left = null
this.right = null
}
// 内部方法不向外暴露
function compareNode(node, newNode) {
if (node.key < newNode.key) { //向右
// 判断是否有子节点
if (node.right) { //有 继续比较
compareNode(node.right, newNode)
} else { //没有 插入
node.right = newNode
_this.count ++
}
} else if (node.key === newNode.key) { //如果key相同 进行修改操作
node.value = newNode.value
} else { // 向左
if (node.left) {
compareNode(node.left, newNode)
} else {
node.left = newNode
_this.count ++
}
}
}
function handlePreOrderTraversal(node, handler) {
if (node) {
// console.log(node.key)
handler(node)
// 先向左边遍历
handlePreOrderTraversal(node.left, handler)
// 再向右遍历
handlePreOrderTraversal(node.right, handler)
}
}
function handleMidOrderTraversal(node, handler) {
if (node) {
// 先向左边遍历
handleMidOrderTraversal(node.left, handler)
handler(node)
// 再向右遍历
handleMidOrderTraversal(node.right, handler)
}
}
function handlerPostOrderTraversal(node, handler) {
if (node) {
handlerPostOrderTraversal(node.left, handler)
handlerPostOrderTraversal(node.right, handler)
handler(node)
}
}
function searchNode(node, key) {
if (!node) {
return
}
if (key < node.key) { //向左
searchNode(node.left, key)
} else if (key > node.key) { // 向右
searchNode(node.right, key)
} else { //相等
nodeValue = node.value
}
}
// 获取后继
function getSuccessor(node) {
node = node.right
while (node.left) {
node = node.left
}
return node
}
// 1.插入方法 递归
BinarySearchTree.prototype.insert = function (key, value) {
let newNode = new Node(key, value)
if (this.root === null) {
this.root = newNode
this.count ++
} else { // 根结点存在 并进行比较
compareNode(this.root, newNode)
}
}
// 2.先序遍历 递归
BinarySearchTree.prototype.preOrderTraversal = function (handler) {
handlePreOrderTraversal(this.root, handler)
}
// 3.中序遍历
BinarySearchTree.prototype.midOrderTraversal = function (handler) {
handleMidOrderTraversal(this.root, handler)
}
// 4.后序遍历
BinarySearchTree.prototype.postOrderTraversal = function (handler) {
handlerPostOrderTraversal(this.root, handler)
}
// 5. 最大 最小值
BinarySearchTree.prototype.max = function () {
let node = this.root
while (node.right) {
node = node.right
}
return node.key
}
BinarySearchTree.prototype.min = function () {
let node = this.root
while (node.left) {
node = node.left
}
return node.key
}
// 6. 搜索特定的值
BinarySearchTree.prototype.search = function (key) {
nodeValue = ''
// 递归
searchNode(this.root, key)
if (nodeValue === undefined || nodeValue) {
return nodeValue
} else {
return false
}
return nodeValue
}
// 7.删除方法
BinarySearchTree.prototype.delete = function (key) {
let current = this.root
let parent = null
let isLeft = null
// 1 先查找到该 key 值的结点
while (current.key !== key) {
if (key > current.key) {
parent = current
current = current.right
} else if (key < current.key) {
parent = current
current = current.left
}
// 找到最后也没有找到
if (current === null) return false
}
// 成功找到
if (parent && parent.left === current) {
isLeft = true
} else {
isLeft = false
}
// 情况1 删除的是叶子结点
if (!current.left && !current.right) {
if (current === this.root) {
this.root = null
this.count --
return true
}
if (isLeft) {
parent.left = null
} else {
parent.right = null
}
} else if ((current.left && !current.right) || (!current.left && current.right)) {
//情况2 只有一个子结点 左或者右
if (current === this.root) {
if (current.left) {
this.root = current.left
} else {
this.root = current.right
}
this.count --
return true
}
if (isLeft) {
if (current.left) {
parent.left = current.left
} else {
parent.left = current.right
}
} else {
if (current.left) {
parent.right = current.left
} else {
parent.right = current.right
}
}
} else {
// 情况3 有两个子结点
// 特殊 删除的是根结点
if (current === this.root) {
// 这里就需要获取到 先驱 或 后继
let successor = getSuccessor(current)
//重新遍历 获得与successor相同的结点和他的pre
let cur = this.root
let pre = null
while (cur.key !== successor.key) {
if (cur.key > successor.key) {
pre = cur
cur = cur.left
} else {
pre = cur
cur = cur.right
}
}
if (pre.left === cur) {
// 由于successor 是最小的 所以他下面只会有右结点
pre.left = cur.right
} else {
pre.right = cur.right
}
successor.left = this.root.left
successor.right = this.root.right
this.root = successor
} else { //不是根
let successor = getSuccessor(current)
let cur = this.root
let pre = null
while (cur.key !== successor.key) {
if (cur.key > successor.key) {
pre = cur
cur = cur.left
} else {
pre = cur
cur = cur.right
}
}
if (pre.left === cur) {
// 由于successor 是最小的 所以他下面只会有右结点
pre.left = cur.right
} else {
pre.right = cur.right
}
if (isLeft) {
parent.left = successor
} else {
parent.right = successor
}
successor.left = current.left
successor.right = current.right
}
}
this.count --
}
}
let bt = new BinarySearchTree()
bt.insert(11)
bt.insert(7)
bt.insert(5)
bt.insert(3, '22')
bt.insert(9)
bt.insert(8)
bt.insert(10)
bt.insert(15)
bt.insert(13)
bt.insert(12)
bt.insert(14)
bt.insert(20)
bt.insert(18)
bt.insert(19)
bt.insert(25)
console.log(bt)
bt.delete(15)
console.log(bt)
// bt.insert(3)
// bt.insert(2)
// bt.insert(1, 'kele')
// bt.insert(5, 'litokele')
// bt.insert(4)
// bt.insert(6)
// bt.insert(10)
// bt.insert(9)
// console.log(bt)
// let str = ''
// bt.preOrderTraversal(node => str += node.key + ' ')
// console.log('先序' + str)
// str = ''
// bt.midOrderTraversal(function (node) {
// str += node.key + ' '
// })
// console.log('中序' + str)
// str = ''
// bt.postOrderTraversal(node => str += node.key + ' ')
// console.log('后序' + str)
// console.log('最大值' + bt.max())
// console.log('最小值' + bt.min())
// console.log(bt.search(1))
// console.log(bt.search(5))
// console.log(bt.search(4))
</script>
</body>
</html>