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Commit fd7da22

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增加二叉搜索树的封装
1 parent d858d11 commit fd7da22

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3 files changed

+317
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lines changed

3 files changed

+317
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lines changed

‎src/Tree/index.js

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import { BinarySearchTree } from './tree';
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// ---------------- 封装的树结构测试 ---------------- //
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console.log('// ----- 树结构测试 START -----//');
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// 二叉搜索树测试
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// insert() 插入
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const binarySearchTree = new BinarySearchTree();
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binarySearchTree.insert(11);
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binarySearchTree.insert(7);
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binarySearchTree.insert(5);
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binarySearchTree.insert(3);
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binarySearchTree.insert(9);
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binarySearchTree.insert(8);
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binarySearchTree.insert(10);
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binarySearchTree.insert(15);
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binarySearchTree.insert(13);
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binarySearchTree.insert(12);
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binarySearchTree.insert(14);
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binarySearchTree.insert(20);
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binarySearchTree.insert(18);
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binarySearchTree.insert(25);
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binarySearchTree.insert(19);
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console.log(binarySearchTree);
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console.log('前序遍历', binarySearchTree.preorderTraversal());
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console.log('中序遍历', binarySearchTree.inorderTraversal());
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console.log('后序遍历', binarySearchTree.postorderTraversal());
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console.log('min', binarySearchTree.min());
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console.log('max', binarySearchTree.max());
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console.log('search(98)-递归实现', binarySearchTree.search(98));
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console.log('search(10)-递归实现', binarySearchTree.search(10));
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console.log('search(98)-while循环实现', binarySearchTree.search2(98));
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console.log('search(10)-while循环实现', binarySearchTree.search2(10));
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console.log('remove(20)');
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binarySearchTree.remove(20);
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console.log(binarySearchTree);
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console.log(binarySearchTree.inorderTraversal());
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console.log('// -----树结构测试 END -----//');
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‎src/Tree/tree.js

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// 节点类
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class Node {
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constructor(key) {
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this.key = key;
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this.left = null;
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this.right = null;
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}
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}
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// 封装二叉搜索树(特点:左子树节点值 < 根节点,右子树节点值 > 根节点)
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export class BinarySearchTree {
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constructor() {
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this.root = null;
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}
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// insert(key) 插入数据
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insert(key) {
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const newNode = new Node(key);
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if (this.root === null) {
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this.root = newNode;
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} else {
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this.insertNode(this.root, newNode);
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}
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}
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insertNode(root, node) {
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if (node.key < root.key) { // 往左边查找插入
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if (root.left === null) {
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root.left = node;
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} else {
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this.insertNode(root.left, node);
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}
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} else { // 往右边查找插入
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if (root.right === null) {
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root.right = node;
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} else {
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this.insertNode(root.right, node);
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}
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}
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}
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// ----------- 二叉树遍历 ----------- //
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// 先序遍历(根左右 DLR)
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preorderTraversal() {
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const result = [];
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this.preorderTraversalNode(this.root, result);
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return result;
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}
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preorderTraversalNode(node, result) {
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if (node === null) return result;
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result.push(node.key);
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this.preorderTraversalNode(node.left, result);
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this.preorderTraversalNode(node.right, result);
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}
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// 中序遍历(左根右 LDR)
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inorderTraversal() {
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const result = [];
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this.inorderTraversalNode(this.root, result);
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return result;
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}
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inorderTraversalNode(node, result) {
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if (node === null) return result;
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this.inorderTraversalNode(node.left, result);
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result.push(node.key);
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this.inorderTraversalNode(node.right, result);
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}
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// 后序遍历(左右根 LRD)
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postorderTraversal() {
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const result = [];
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this.postorderTraversalNode(this.root, result);
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return result;
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}
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postorderTraversalNode(node, result) {
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if (node === null) return result;
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this.postorderTraversalNode(node.left, result);
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this.postorderTraversalNode(node.right, result);
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result.push(node.key);
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}
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// min() 获取二叉搜索树最小值
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min() {
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if (!this.root) return null;
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let node = this.root;
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while (node.left !== null) {
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node = node.left;
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}
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return node.key;
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}
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// max() 获取二叉搜索树最大值
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max() {
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if (!this.root) return null;
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let node = this.root;
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while (node.right !== null) {
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node = node.right;
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}
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return node.key;
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}
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// search(key) 查找二叉搜索树中是否有相同的key,存在返回 true,否则返回 false
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search(key) {
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return this.searchNode(this.root, key);
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}
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// 通过递归实现
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searchNode(node, key) {
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if (node === null) return false;
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if (key < node.key) {
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return this.searchNode(node.left, key);
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} else if (key > node.key) {
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return this.searchNode(node.right, key);
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} else {
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return true;
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}
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}
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// 通过 while 循环实现
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search2(key) {
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let node = this.root;
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while (node !== null) {
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if (key < node.key) {
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node = node.left;
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} else if (key > node.key) {
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node = node.right;
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} else {
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return true;
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}
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}
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return false;
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}
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// 删除节点
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remove(key) {
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let currentNode = this.root;
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let parentNode = null;
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let isLeftChild = true;
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// 循环查找到要删除的节点 currentNode,以及它的 parentNode、isLeftChild
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while (currentNode.key !== key) {
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parentNode = currentNode;
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// 小于,往左查找
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if (key < currentNode.key) {
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isLeftChild = true;
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currentNode = currentNode.left;
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} else { // 否则往右查找
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isLeftChild = false;
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currentNode = currentNode.right;
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}
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// 找到最后都没找到相等的节点,返回 false
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if (currentNode === null) {
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return false;
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}
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}
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// 1、删除的是叶子节点的情况
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if (currentNode.left === null && currentNode.right === null) {
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if (currentNode === this.root) {
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this.root = null;
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} else if (isLeftChild) {
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parentNode.left = null;
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} else {
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parentNode.right = null;
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}
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// 2、删除的是只有一个子节点的节点
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} else if (currentNode.right === null) { // currentNode 只存在左节点
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//-- 2.1、currentNode 只存在<左节点>的情况
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//---- 2.1.1、currentNode 等于 root
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//---- 2.1.2、parentNode.left 等于 currentNode
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//---- 2.1.3、parentNode.right 等于 currentNode
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if (currentNode === this.root) {
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this.root = currentNode.left;
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} else if (isLeftChild) {
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parentNode.left = currentNode.left;
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} else {
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parentNode.right = currentNode.left;
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}
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} else if (currentNode.left === null) { // currentNode 只存在右节点
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//-- 2.2、currentNode 只存在<右节点>的情况
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//---- 2.1.1 currentNode 等于 root
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//---- 2.1.1 parentNode.left 等于 currentNode
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//---- 2.1.1 parentNode.right 等于 currentNode
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if (currentNode === this.root) {
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this.root = currentNode.right;
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} else if (isLeftChild) {
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parentNode.left = currentNode.right;
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} else {
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parentNode.right = currentNode.right;
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}
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// 3、删除的是有两个子节点的节点
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} else {
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// 1、找到后续节点
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let successor = this.getSuccessor(currentNode);
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// 2、判断是否为根节点
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if (currentNode === this.root) {
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this.root = successor;
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} else if (isLeftChild) {
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parentNode.left = successor;
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} else {
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parentNode.right = successor;
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}
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// 3、将后续的左节点改为被删除的左节点
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successor.left = currentNode.left;
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}
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}
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// 获取后续节点,即从要删除的节点的右边开始查找最小的值
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getSuccessor(delNode) {
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// 定义变量,保存要找到的后续
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let successor = delNode;
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let current = delNode.right;
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let successorParent = delNode;
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// 循环查找 current 的右子树节点
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while (current !== null) {
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successorParent = successor;
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successor = current;
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current = current.left;
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}
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// 判断寻找到的后续节点是否直接就是要删除节点的 right
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if (successor !== delNode.right) {
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successorParent.left = successor.right;
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successor.right = delNode.right;
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}
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return successor;
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}
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}

‎src/index.js

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// import './Map'
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// 导入哈希表结构的封装及测试代码
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import './HashTable';
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// import './HashTable';
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// 导入树结构的封装及测试代码
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import './Tree';

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