Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

feat(tree): Add the array representation of the binary tree(js,ts) #681

Merged
merged 3 commits into from
Aug 13, 2023
Merged

feat(tree): Add the array representation of the binary tree(js,ts) #681

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
2d2a711
fix: fixed the bug of arrToTree function
yuan0221 Aug 10, 2023
cdffcc7
feat(tree): Add the array representation of the binary tree(js,ts)
yuan0221 Aug 10, 2023
76d65c7
refactor: Make the arrToTree method match the method in java
yuan0221 Aug 11, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
147 changes: 147 additions & 0 deletions codes/javascript/chapter_tree/array_binary_tree.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,147 @@
/**
* File: array_binary_tree.js
* Created Time: 2023-08-06
* Author: yuan0221 ([email protected])
*/

const { arrToTree } = require('../modules/TreeNode');
const { printTree } = require('../modules/PrintUtil');

/* 数组表示下的二叉树类 */
class ArrayBinaryTree {
#tree;

/* 构造方法 */
constructor(arr) {
this.#tree = arr;
}

/* 节点数量 */
size() {
return this.#tree.length;
}

/* 获取索引为 i 节点的值 */
val(i) {
// 若索引越界，则返回 null ，代表空位
if (i < 0 || i >= this.size()) return null;
return this.#tree[i];
}

/* 获取索引为 i 节点的左子节点的索引 */
left(i) {
return 2 * i + 1;
}

/* 获取索引为 i 节点的右子节点的索引 */
right(i) {
return 2 * i + 2;
}

/* 获取索引为 i 节点的父节点的索引 */
parent(i) {
return (i - 1) / 2;
}

/* 层序遍历 */
levelOrder() {
let res = [];
// 直接遍历数组
for (let i = 0; i < this.size(); i++) {
if (this.val(i) !== null) res.push(this.val(i));
}
return res;
}

/* 深度优先遍历 */
#dfs(i, order, res) {
// 若为空位，则返回
if (this.val(i) === null) return;
// 前序遍历
if (order === 'pre') res.push(this.val(i));
this.#dfs(this.left(i), order, res);
// 中序遍历
if (order === 'in') res.push(this.val(i));
this.#dfs(this.right(i), order, res);
// 后序遍历
if (order === 'post') res.push(this.val(i));
}

/* 前序遍历 */
preOrder() {
const res = [];
this.#dfs(0, 'pre', res);
return res;
}

/* 中序遍历 */
inOrder() {
const res = [];
this.#dfs(0, 'in', res);
return res;
}

/* 后序遍历 */
postOrder() {
const res = [];
this.#dfs(0, 'post', res);
return res;
}
}

/* Driver Code */
// 初始化二叉树
// 这里借助了一个从数组直接生成二叉树的函数
const arr = Array.of(
1,
2,
3,
4,
null,
6,
7,
8,
9,
null,
null,
12,
null,
null,
15
);

const root = arrToTree(arr);
console.log('\n初始化二叉树\n');
console.log('二叉树的数组表示：');
console.log(arr);
console.log('二叉树的链表表示：');
printTree(root);

// 数组表示下的二叉树类
const abt = new ArrayBinaryTree(arr);

// 访问节点
const i = 1;
const l = abt.left(i);
const r = abt.right(i);
const p = abt.parent(i);
console.log('\n当前节点的索引为 ' + i + ' ，值为 ' + abt.val(i));
console.log(
'其左子节点的索引为 ' + l + ' ，值为 ' + (l === null ? 'null' : abt.val(l))
);
console.log(
'其右子节点的索引为 ' + r + ' ，值为 ' + (r === null ? 'null' : abt.val(r))
);
console.log(
'其父节点的索引为 ' + p + ' ，值为 ' + (p === null ? 'null' : abt.val(p))
);

// 遍历树
let res = abt.levelOrder();
console.log('\n层序遍历为：' + res);
res = abt.preOrder();
console.log('前序遍历为：' + res);
res = abt.inOrder();
console.log('中序遍历为：' + res);
res = abt.postOrder();
console.log('后序遍历为：' + res);
25 changes: 6 additions & 19 deletions codes/javascript/modules/TreeNode.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,26 +25,13 @@ class TreeNode {
* @param arr
* @return
*/
function arrToTree(arr) {
if (arr.length === 0) return null;

let root = new TreeNode(arr[0]);
let queue = [root];
let i = 0;
while (queue.length) {
let node = queue.shift();
if (++i >= arr.length) break;
if (arr[i] !== null) {
node.left = new TreeNode(arr[i]);
queue.push(node.left);
}
if (++i >= arr.length) break;
if (arr[i] !== null) {
node.right = new TreeNode(arr[i]);
queue.push(node.right);
}
function arrToTree(arr, i = 0) {
if (i < 0 || i >= arr.length || arr[i] === null) {
return null;
}

let root = new TreeNode(arr[i]);
root.left = arrToTree(arr, 2 * i + 1);
root.right = arrToTree(arr, 2 * i + 2);
return root;
}

Expand Down
151 changes: 151 additions & 0 deletions codes/typescript/chapter_tree/array_binary_tree.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,151 @@
/**
* File: array_binary_tree.js
* Created Time: 2023-08-09
* Author: yuan0221 ([email protected])
*/

const { arrToTree } = require('../modules/TreeNode');
const { printTree } = require('../modules/PrintUtil');

type Order = 'pre' | 'in' | 'post';

/* 数组表示下的二叉树类 */
class ArrayBinaryTree {
#tree: (number | null)[];

/* 构造方法 */
constructor(arr: (number | null)[]) {
this.#tree = arr;
}

/* 节点数量 */
size(): number {
return this.#tree.length;
}

/* 获取索引为 i 节点的值 */
val(i: number): number | null {
// 若索引越界，则返回 null ，代表空位
if (i < 0 || i >= this.size()) return null;
return this.#tree[i];
}

/* 获取索引为 i 节点的左子节点的索引 */
left(i: number): number {
return 2 * i + 1;
}

/* 获取索引为 i 节点的右子节点的索引 */
right(i: number): number {
return 2 * i + 2;
}

/* 获取索引为 i 节点的父节点的索引 */
parent(i: number): number {
return (i - 1) / 2;
}

/* 层序遍历 */
levelOrder(): number[] {
let res = [];
// 直接遍历数组
for (let i = 0; i < this.size(); i++) {
if (this.val(i) !== null) res.push(this.val(i));
}
return res;
}

/* 深度优先遍历 */
#dfs(i: number, order: Order, res: (number | null)[]): void {
// 若为空位，则返回
if (this.val(i) === null) return;
// 前序遍历
if (order === 'pre') res.push(this.val(i));
this.#dfs(this.left(i), order, res);
// 中序遍历
if (order === 'in') res.push(this.val(i));
this.#dfs(this.right(i), order, res);
// 后序遍历
if (order === 'post') res.push(this.val(i));
}

/* 前序遍历 */
preOrder(): (number | null)[] {
const res = [];
this.#dfs(0, 'pre', res);
return res;
}

/* 中序遍历 */
inOrder(): (number | null)[] {
const res = [];
this.#dfs(0, 'in', res);
return res;
}

/* 后序遍历 */
postOrder(): (number | null)[] {
const res = [];
this.#dfs(0, 'post', res);
return res;
}
}

/* Driver Code */
// 初始化二叉树
// 这里借助了一个从数组直接生成二叉树的函数
const arr = Array.of(
1,
2,
3,
4,
null,
6,
7,
8,
9,
null,
null,
12,
null,
null,
15
);

const root = arrToTree(arr);
console.log('\n初始化二叉树\n');
console.log('二叉树的数组表示：');
console.log(arr);
console.log('二叉树的链表表示：');
printTree(root);

// 数组表示下的二叉树类
const abt = new ArrayBinaryTree(arr);

// 访问节点
const i = 1;
const l = abt.left(i);
const r = abt.right(i);
const p = abt.parent(i);
console.log('\n当前节点的索引为 ' + i + ' ，值为 ' + abt.val(i));
console.log(
'其左子节点的索引为 ' + l + ' ，值为 ' + (l === null ? 'null' : abt.val(l))
);
console.log(
'其右子节点的索引为 ' + r + ' ，值为 ' + (r === null ? 'null' : abt.val(r))
);
console.log(
'其父节点的索引为 ' + p + ' ，值为 ' + (p === null ? 'null' : abt.val(p))
);

// 遍历树
let res = abt.levelOrder();
console.log('\n层序遍历为：' + res);
res = abt.preOrder();
console.log('前序遍历为：' + res);
res = abt.inOrder();
console.log('中序遍历为：' + res);
res = abt.postOrder();
console.log('后序遍历为：' + res);

export {};
24 changes: 5 additions & 19 deletions codes/typescript/modules/TreeNode.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -30,27 +30,13 @@ class TreeNode {
* @param arr
* @return
*/
function arrToTree(arr: (number | null)[]): TreeNode | null {
if (arr.length === 0) {
function arrToTree(arr: (number | null)[], i: number = 0): TreeNode | null {
if (i < 0 || i >= arr.length || arr[i] === null) {
return null;
}

const root = new TreeNode(arr[0] as number);
const queue = [root];
let i = 0;
while (queue.length) {
const node = queue.shift() as TreeNode;
if (++i >= arr.length) break;
if (arr[i] !== null) {
node.left = new TreeNode(arr[i] as number);
queue.push(node.left);
}
if (++i >= arr.length) break;
if (arr[i] !== null) {
node.right = new TreeNode(arr[i] as number);
queue.push(node.right);
}
}
let root = new TreeNode(arr[i]);
root.left = arrToTree(arr, 2 * i + 1);
root.right = arrToTree(arr, 2 * i + 2);
return root;
}

Expand Down