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add JavaScript codes for Tree
This commit is contained in:
IsChristina
parent
ebf9024136
commit
db416cf4bb
7 changed files with 462 additions and 5 deletions
145
codes/javascript/chapter_tree/binary_search_tree.js
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145
codes/javascript/chapter_tree/binary_search_tree.js
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@ -0,0 +1,145 @@
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/**
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* File: binary_tree.js
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* Created Time: 2022-12-04
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* Author: IsChristina (christinaxia77@foxmail.com)
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*/
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const Tree = require("../include/TreeNode");
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/* 二叉搜索树 */
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var root;
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function BinarySearchTree(nums) {
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nums.sort((a,b) => { return a-b }); // 排序数组
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root = buildTree(nums, 0, nums.length - 1); // 构建二叉搜索树
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}
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/* 获取二叉树根结点 */
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function getRoot() {
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return root;
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}
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/* 构建二叉搜索树 */
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function buildTree(nums, i, j) {
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if (i > j) return null;
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// 将数组中间结点作为根结点
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let mid = Math.floor((i + j) / 2);
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let root = new Tree.TreeNode(nums[mid]);
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// 递归建立左子树和右子树
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root.left = buildTree(nums, i, mid - 1);
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root.right = buildTree(nums, mid + 1, j);
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return root;
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}
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/* 查找结点 */
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function search(num) {
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let cur = root;
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// 循环查找，越过叶结点后跳出
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while (cur !== null) {
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// 目标结点在 root 的右子树中
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if (cur.val < num) cur = cur.right;
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// 目标结点在 root 的左子树中
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else if (cur.val > num) cur = cur.left;
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// 找到目标结点，跳出循环
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else break;
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}
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// 返回目标结点
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return cur;
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}
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/* 插入结点 */
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function insert(num) {
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// 若树为空，直接提前返回
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if (root === null) return null;
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let cur = root, pre = null;
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// 循环查找，越过叶结点后跳出
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while (cur !== null) {
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// 找到重复结点，直接返回
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if (cur.val === num) return null;
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pre = cur;
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// 插入位置在 root 的右子树中
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if (cur.val < num) cur = cur.right;
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// 插入位置在 root 的左子树中
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else cur = cur.left;
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}
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// 插入结点 val
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let node = new Tree.TreeNode(num);
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if (pre.val < num) pre.right = node;
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else pre.left = node;
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return node;
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}
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/* 删除结点 */
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function remove(num) {
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// 若树为空，直接提前返回
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if (root === null) return null;
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let cur = root, pre = null;
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// 循环查找，越过叶结点后跳出
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while (cur !== null) {
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// 找到待删除结点，跳出循环
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if (cur.val === num) break;
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pre = cur;
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// 待删除结点在 root 的右子树中
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if (cur.val < num) cur = cur.right;
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// 待删除结点在 root 的左子树中
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else cur = cur.left;
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}
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// 若无待删除结点，则直接返回
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if (cur === null) return null;
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// 子结点数量 = 0 or 1
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if (cur.left === null || cur.right === null) {
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// 当子结点数量 = 0 / 1 时， child = null / 该子结点
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let child = cur.left !== null ? cur.left : cur.right;
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// 删除结点 cur
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if (pre.left === cur) pre.left = child;
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else pre.right = child;
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}
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// 子结点数量 = 2
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else {
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// 获取中序遍历中 cur 的下一个结点
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let nex = min(cur.right);
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let tmp = nex.val;
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// 递归删除结点 nex
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remove(nex.val);
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// 将 nex 的值复制给 cur
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cur.val = tmp;
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}
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return cur;
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}
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/* 获取最小结点 */
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function min(root) {
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if (root === null) return root;
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// 循环访问左子结点，直到叶结点时为最小结点，跳出
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while (root.left !== null) {
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root = root.left;
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}
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return root;
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}
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/* Driver Code */
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/* 初始化二叉搜索树 */
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var nums = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 ];
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BinarySearchTree(nums)
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console.log("\n初始化的二叉树为\n");
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console.log(getRoot());
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/* 查找结点 */
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let node = search(5);
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console.log("\n查找到的结点对象为 " + node + "，结点值 = " + node.val);
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/* 插入结点 */
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node = insert(16);
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console.log("\n插入结点 16 后，二叉树为\n");
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console.log(getRoot());
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/* 删除结点 */
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remove(1);
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console.log("\n删除结点 1 后，二叉树为\n");
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console.log(getRoot());
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remove(2);
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console.log("\n删除结点 2 后，二叉树为\n");
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console.log(getRoot());
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remove(4);
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console.log("\n删除结点 4 后，二叉树为\n");
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console.log(getRoot());
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34
codes/javascript/chapter_tree/binary_tree.js
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34
codes/javascript/chapter_tree/binary_tree.js
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@ -0,0 +1,34 @@
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/**
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* File: binary_tree.js
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* Created Time: 2022-12-04
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* Author: IsChristina (christinaxia77@foxmail.com)
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*/
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const Tree = require("../include/TreeNode");
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/* 初始化二叉树 */
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// 初始化结点
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let n1 = new Tree.TreeNode(1),
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n2 = new Tree.TreeNode(2),
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n3 = new Tree.TreeNode(3),
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n4 = new Tree.TreeNode(4),
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n5 = new Tree.TreeNode(5);
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// 构建引用指向（即指针）
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n1.left = n2;
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n1.right = n3;
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n2.left = n4;
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n2.right = n5;
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console.log("\n初始化二叉树\n")
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console.log(n1)
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/* 插入与删除结点 */
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let P = new Tree.TreeNode(0);
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// 在 n1 -> n2 中间插入结点 P
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n1.left = P;
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P.left = n2;
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console.log("\n插入结点 P 后\n");
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console.log(n1);
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// 删除结点 P
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n1.left = n2;
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console.log("\n删除结点 P 后\n");
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console.log(n1);
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36
codes/javascript/chapter_tree/binary_tree_bfs.js
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36
codes/javascript/chapter_tree/binary_tree_bfs.js
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/**
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* File: binary_tree.js
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* Created Time: 2022-12-04
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* Author: IsChristina (christinaxia77@foxmail.com)
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*/
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let { arrToTree } = require("../include/TreeNode");
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/* 层序遍历 */
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function hierOrder(root) {
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// 初始化队列，加入根结点
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let queue = [root];
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// 初始化一个列表，用于保存遍历序列
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let list = [];
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while (queue.length) {
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let node = queue.shift(); // 队列出队
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list.push(node.val); // 保存结点
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if (node.left)
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queue.push(node.left); // 左子结点入队
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if (node.right)
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queue.push(node.right); // 右子结点入队
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}
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return list;
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}
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/* Driver Code */
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/* 初始化二叉树 */
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// 这里借助了一个从数组直接生成二叉树的函数
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var root = arrToTree([1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null ]);
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console.log("\n初始化二叉树\n");
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console.log(root);
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/* 层序遍历 */
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let list = hierOrder(root);
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console.log("\n层序遍历的结点打印序列 = " + list);
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60
codes/javascript/chapter_tree/binary_tree_dfs.js
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60
codes/javascript/chapter_tree/binary_tree_dfs.js
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/**
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* File: binary_tree.js
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* Created Time: 2022-12-04
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* Author: IsChristina (christinaxia77@foxmail.com)
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*/
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let { arrToTree } = require("../include/TreeNode");
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// 初始化列表，用于存储遍历序列
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var list = []
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/* 前序遍历 */
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function preOrder(root){
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if (root === null) return;
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// 访问优先级：根结点 -> 左子树 -> 右子树
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list.push(root.val);
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preOrder(root.left);
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preOrder(root.right);
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}
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/* 中序遍历 */
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function inOrder(root) {
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if (root === null) return;
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// 访问优先级：左子树 -> 根结点 -> 右子树
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inOrder(root.left);
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list.push(root.val);
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inOrder(root.right);
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}
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/* 后序遍历 */
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function postOrder(root) {
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if (root === null) return;
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// 访问优先级：左子树 -> 右子树 -> 根结点
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postOrder(root.left);
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postOrder(root.right);
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list.push(root.val);
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}
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/* Driver Code */
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/* 初始化二叉树 */
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// 这里借助了一个从数组直接生成二叉树的函数
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var root = arrToTree([1, 2, 3, 4, 5, 6, 7, null, null, null, null, null, null, null, null]);
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console.log("\n初始化二叉树\n");
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console.log(root);
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/* 前序遍历 */
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list.length = 0;
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preOrder(root);
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console.log("\n前序遍历的结点打印序列 = " + list);
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/* 中序遍历 */
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list.length = 0;
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inOrder(root);
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console.log("\n中序遍历的结点打印序列 = " + list);
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/* 后序遍历 */
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list.length = 0;
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postOrder(root);
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console.log("\n后序遍历的结点打印序列 = " + list);
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47
codes/javascript/include/TreeNode.js
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47
codes/javascript/include/TreeNode.js
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/**
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* File: TreeNode.js
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* Created Time: 2022-12-04
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* Author: IsChristina (christinaxia77@foxmail.com)
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*/
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/**
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* Definition for a binary tree node.
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*/
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function TreeNode(val, left, right) {
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this.val = (val === undefined ? 0 : val) // 结点值
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this.left = (left === undefined ? null : left) // 左子结点指针
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this.right = (right === undefined ? null : right) // 右子结点指针
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}
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/**
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* Generate a binary tree with an array
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* @param arr
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* @return
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*/
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function arrToTree(arr) {
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if (arr.length === 0)
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return null;
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let root = new TreeNode(arr[0]);
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let queue = [root]
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let i = 1;
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while(queue.length) {
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let node = queue.shift();
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if(arr[i] !== null) {
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node.left = new TreeNode(arr[i]);
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queue.push(node.left);
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}
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i++;
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if(arr[i] !== null) {
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node.right = new TreeNode(arr[i]);
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queue.push(node.right);
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}
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i++;
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}
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return root;
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}
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module.exports = {
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TreeNode,
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arrToTree,
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}
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@ -112,7 +112,21 @@ comments: true
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=== "JavaScript"
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```js title="binary_search_tree.js"
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/* 查找结点 */
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function search(num) {
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let cur = root;
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// 循环查找，越过叶结点后跳出
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while (cur !== null) {
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// 目标结点在 root 的右子树中
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if (cur.val < num) cur = cur.right;
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// 目标结点在 root 的左子树中
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else if (cur.val > num) cur = cur.left;
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// 找到目标结点，跳出循环
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else break;
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}
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// 返回目标结点
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return cur;
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}
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```
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=== "TypeScript"
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@ -240,7 +254,27 @@ comments: true
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=== "JavaScript"
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```js title="binary_search_tree.js"
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/* 插入结点 */
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function insert(num) {
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// 若树为空，直接提前返回
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if (root === null) return null;
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let cur = root, pre = null;
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// 循环查找，越过叶结点后跳出
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while (cur !== null) {
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// 找到重复结点，直接返回
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if (cur.val === num) return null;
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pre = cur;
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// 插入位置在 root 的右子树中
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if (cur.val < num) cur = cur.right;
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// 插入位置在 root 的左子树中
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else cur = cur.left;
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}
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// 插入结点 val
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let node = new Tree.TreeNode(num);
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if (pre.val < num) pre.right = node;
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else pre.left = node;
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return node;
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}
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```
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=== "TypeScript"
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@ -471,7 +505,43 @@ comments: true
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=== "JavaScript"
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```js title="binary_search_tree.js"
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/* 删除结点 */
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function remove(num) {
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// 若树为空，直接提前返回
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if (root === null) return null;
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let cur = root, pre = null;
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// 循环查找，越过叶结点后跳出
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while (cur !== null) {
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// 找到待删除结点，跳出循环
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if (cur.val === num) break;
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pre = cur;
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// 待删除结点在 root 的右子树中
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if (cur.val < num) cur = cur.right;
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// 待删除结点在 root 的左子树中
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else cur = cur.left;
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}
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// 若无待删除结点，则直接返回
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if (cur === null) return null;
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// 子结点数量 = 0 or 1
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if (cur.left === null || cur.right === null) {
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// 当子结点数量 = 0 / 1 时， child = null / 该子结点
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let child = cur.left !== null ? cur.left : cur.right;
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// 删除结点 cur
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if (pre.left === cur) pre.left = child;
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else pre.right = child;
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}
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// 子结点数量 = 2
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else {
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// 获取中序遍历中 cur 的下一个结点
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let nex = min(cur.right);
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let tmp = nex.val;
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// 递归删除结点 nex
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remove(nex.val);
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// 将 nex 的值复制给 cur
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cur.val = tmp;
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}
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return cur;
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}
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```
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=== "TypeScript"
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@ -63,6 +63,12 @@ comments: true
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=== "JavaScript"
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```js title=""
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/* 链表结点类 */
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function TreeNode(val, left, right) {
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this.val = (val === undefined ? 0 : val) // 结点值
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this.left = (left === undefined ? null : left) // 左子结点指针
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this.right = (right === undefined ? null : right) // 右子结点指针
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}
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```
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|
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@ -193,7 +199,18 @@ comments: true
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=== "JavaScript"
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```js title="binary_tree.js"
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/* 初始化二叉树 */
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||||
// 初始化结点
|
||||
let n1 = new TreeNode(1),
|
||||
n2 = new TreeNode(2),
|
||||
n3 = new TreeNode(3),
|
||||
n4 = new TreeNode(4),
|
||||
n5 = new TreeNode(5);
|
||||
// 构建引用指向（即指针）
|
||||
n1.left = n2;
|
||||
n1.right = n3;
|
||||
n2.left = n4;
|
||||
n2.right = n5;
|
||||
```
|
||||
|
||||
=== "TypeScript"
|
||||
|
|
@ -265,7 +282,14 @@ comments: true
|
|||
=== "JavaScript"
|
||||
|
||||
```js title="binary_tree.js"
|
||||
/* 插入与删除结点 */
|
||||
let P = new TreeNode(0);
|
||||
// 在 n1 -> n2 中间插入结点 P
|
||||
n1.left = P;
|
||||
P.left = n2;
|
||||
|
||||
// 删除结点 P
|
||||
n1.left = n2;
|
||||
```
|
||||
|
||||
=== "TypeScript"
|
||||
|
|
@ -387,7 +411,23 @@ comments: true
|
|||
=== "JavaScript"
|
||||
|
||||
```js title="binary_tree_bfs.js"
|
||||
|
||||
/* 层序遍历 */
|
||||
function hierOrder(root) {
|
||||
// 初始化队列，加入根结点
|
||||
let queue = [root];
|
||||
// 初始化一个列表，用于保存遍历序列
|
||||
let list = [];
|
||||
while (queue.length) {
|
||||
let node = queue.shift(); // 队列出队
|
||||
list.push(node.val); // 保存结点
|
||||
if (node.left)
|
||||
queue.push(node.left); // 左子结点入队
|
||||
if (node.right)
|
||||
queue.push(node.right); // 右子结点入队
|
||||
|
||||
}
|
||||
return list;
|
||||
}
|
||||
```
|
||||
|
||||
=== "TypeScript"
|
||||
|
|
@ -536,7 +576,32 @@ comments: true
|
|||
=== "JavaScript"
|
||||
|
||||
```js title="binary_tree_dfs.js"
|
||||
/* 前序遍历 */
|
||||
function preOrder(root){
|
||||
if (root === null) return;
|
||||
// 访问优先级：根结点 -> 左子树 -> 右子树
|
||||
list.push(root.val);
|
||||
preOrder(root.left);
|
||||
preOrder(root.right);
|
||||
}
|
||||
|
||||
/* 中序遍历 */
|
||||
function inOrder(root) {
|
||||
if (root === null) return;
|
||||
// 访问优先级：左子树 -> 根结点 -> 右子树
|
||||
inOrder(root.left);
|
||||
list.push(root.val);
|
||||
inOrder(root.right);
|
||||
}
|
||||
|
||||
/* 后序遍历 */
|
||||
function postOrder(root) {
|
||||
if (root === null) return;
|
||||
// 访问优先级：左子树 -> 右子树 -> 根结点
|
||||
postOrder(root.left);
|
||||
postOrder(root.right);
|
||||
list.push(root.val);
|
||||
}
|
||||
```
|
||||
|
||||
=== "TypeScript"
|
||||
|
|
|
|||
Loading…
Reference in a new issue