Loading...
More JavaScript Posts
class TreeNode {constructor(key, value = key, parent = null) {this.key = key;this.value = value;this.parent = parent;this.children = [];}get isLeaf() {return this.children.length === 0;}get hasChildren() {return !this.isLeaf;}}class Tree {constructor(key, value = key) {this.root = new TreeNode(key, value);}*preOrderTraversal(node = this.root) {yield node;if (node.children.length) {for (let child of node.children) {yield* this.preOrderTraversal(child);}}}*postOrderTraversal(node = this.root) {if (node.children.length) {for (let child of node.children) {yield* this.postOrderTraversal(child);}}yield node;}insert(parentNodeKey, key, value = key) {for (let node of this.preOrderTraversal()) {if (node.key === parentNodeKey) {node.children.push(new TreeNode(key, value, node));return true;}}return false;}remove(key) {for (let node of this.preOrderTraversal()) {const filtered = node.children.filter(c => c.key !== key);if (filtered.length !== node.children.length) {node.children = filtered;return true;}}return false;}find(key) {for (let node of this.preOrderTraversal()) {if (node.key === key) return node;}return undefined;}}const tree = new Tree(1, 'AB');tree.insert(1, 11, 'AC');tree.insert(1, 12, 'BC');tree.insert(12, 121, 'BG');[...tree.preOrderTraversal()].map(x => x.value);// ['AB', 'AC', 'BC', 'BCG']tree.root.value; // 'AB'tree.root.hasChildren; // truetree.find(12).isLeaf; // falsetree.find(121).isLeaf; // truetree.find(121).parent.value; // 'BC'tree.remove(12);[...tree.postOrderTraversal()].map(x => x.value);// ['AC', 'AB']
function printHeap(heap, index, level) {if (index >= heap.length) {return;}console.log(" ".repeat(level) + heap[index]);printHeap(heap, 2 * index + 1, level + 1);printHeap(heap, 2 * index + 2, level + 1);}//You can call this function by passing in the heap array and the index of the root node, which is typically 0, and level = 0.let heap = [3, 8, 7, 15, 17, 30, 35, 2, 4, 5, 9];printHeap(heap,0,0)
/*** @param {number[]} nums* @param {number} target* @return {number[]}*/var twoSum = function(nums, target) {for(let i = 0; i < nums.length; i++) {for(let j = 0; j < nums.length; j++) {if(nums[i] + nums[j] === target && i !== j) {return [i, j]}}}};
// Vanilla JS Solution:var app = document.getElementById('app');var typewriter = new Typewriter(app, { loop: true });typewriter.typeString("I'm John and I'm a super cool web developer").pauseFor(3000).deleteChars(13) // "web developer" = 13 characters.typeString("person to talk with!") // Will display "I'm John and I'm a super cool person to talk with!".start();// React Solution:import Typewriter from 'typewriter-effect';<Typewriteroptions={{ loop: true }}onInit={typewriter => {typewriter.typeString("I'm John and I'm a super cool web developer").pauseFor(3000).deleteChars(13) // "web developer" = 13 characters.typeString("person to talk with!") // Will display "I'm John and I'm a super cool person to talk with!".start();}}/>
const celsiusToFahrenheit = (celsius) => celsius * 9/5 + 32;const fahrenheitToCelsius = (fahrenheit) => (fahrenheit - 32) * 5/9;// ExamplescelsiusToFahrenheit(15); // 59celsiusToFahrenheit(0); // 32celsiusToFahrenheit(-20); // -4fahrenheitToCelsius(59); // 15fahrenheitToCelsius(32); // 0
const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));// Orconst flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);// Or// See the browser compatibility at https://caniuse.com/#feat=array-flatconst flat = arr => arr.flat();// Exampleflat(['cat', ['lion', 'tiger']]); // ['cat', 'lion', 'tiger']