native data structures
0 likes • Nov 19, 2022 • 0 views
JavaScript
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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']
const copyToClipboard = str => {const el = document.createElement('textarea');el.value = str;el.setAttribute('readonly', '');el.style.position = 'absolute';el.style.left = '-9999px';document.body.appendChild(el);const selected =document.getSelection().rangeCount > 0? document.getSelection().getRangeAt(0): false;el.select();document.execCommand('copy');document.body.removeChild(el);if (selected) {document.getSelection().removeAllRanges();document.getSelection().addRange(selected);}};copyToClipboard('Lorem ipsum'); // 'Lorem ipsum' copied to clipboard.
const binomialCoefficient = (n, k) => {if (Number.isNaN(n) || Number.isNaN(k)) return NaN;if (k < 0 || k > n) return 0;if (k === 0 || k === n) return 1;if (k === 1 || k === n - 1) return n;if (n - k < k) k = n - k;let res = n;for (let j = 2; j <= k; j++) res *= (n - j + 1) / j;return Math.round(res);};binomialCoefficient(8, 2); // 28
const geometricProgression = (end, start = 1, step = 2) =>Array.from({length: Math.floor(Math.log(end / start) / Math.log(step)) + 1,}).map((_, i) => start * step ** i);geometricProgression(256); // [1, 2, 4, 8, 16, 32, 64, 128, 256]geometricProgression(256, 3); // [3, 6, 12, 24, 48, 96, 192]geometricProgression(256, 1, 4); // [1, 4, 16, 64, 256]
const Discord = require('discord.js');const client = new Discord.Client();const token = 'YOUR_BOT_TOKEN';// When the bot is ready, log a message to the consoleclient.on('ready', () => {console.log(`Logged in as ${client.user.tag}!`);});// When a user sends a message, check if they are authenticatedclient.on('message', async (msg) => {if (!msg.author.bot && !msg.author.authenticated) {const filter = (m) => m.author.id === msg.author.id;const collector = msg.channel.createMessageCollector(filter, { time: 15000 });// Send an authentication message to the usermsg.author.send('Please authenticate yourself by clicking this link: ' + generateAuthURL(msg.author.id));collector.on('collect', async (m) => {// Check if the message contains the authentication codeif (m.content.startsWith('!auth ')) {const code = m.content.slice(6);const { access_token } = await getAccessToken(code);// Set the user's authenticated status and access tokenmsg.author.authenticated = true;msg.author.access_token = access_token;collector.stop();}});collector.on('end', () => {if (!msg.author.authenticated) {msg.author.send('Authentication timed out.');}});}});// Generate an authentication URL for the userfunction generateAuthURL(userId) {const redirectURI = encodeURIComponent('YOUR_REDIRECT_URL');const scopes = 'identify';const clientID = 'YOUR_CLIENT_ID';return `https://discord.com/api/oauth2/authorize?client_id=${clientID}&redirect_uri=${redirectURI}&response_type=code&scope=${scopes}&state=${userId}`;}// Exchange the authorization code for an access tokenasync function getAccessToken(code) {const redirectURI = encodeURIComponent('YOUR_REDIRECT_URL');const clientID = 'YOUR_CLIENT_ID';const clientSecret = 'YOUR_CLIENT_SECRET';const res = await fetch('https://discord.com/api/oauth2/token', {method: 'POST',headers: {'Content-Type': 'application/x-www-form-urlencoded',},body: `grant_type=authorization_code&code=${code}&redirect_uri=${redirectURI}&client_id=${clientID}&client_secret=${clientSecret}`,});return await res.json();}client.login(token);
// There are n rings and each ring is either red, green, or blue. The rings are distributed across ten rods labeled from 0 to 9.// You are given a string rings of length 2n that describes the n rings that are placed onto the rods. Every two characters in rings forms a color-position pair that is used to describe each ring where:// The first character of the ith pair denotes the ith ring's color ('R', 'G', 'B').// The second character of the ith pair denotes the rod that the ith ring is placed on ('0' to '9').// For example, "R3G2B1" describes n == 3 rings: a red ring placed onto the rod labeled 3, a green ring placed onto the rod labeled 2, and a blue ring placed onto the rod labeled 1.// Return the number of rods that have all three colors of rings on them.let rings = "B0B6G0R6R0R6G9";var countPoints = function(rings) {let sum = 0;// Always 10 Rodsfor (let i = 0; i < 10; i++) {if (rings.includes(`B${i}`) && rings.includes(`G${i}`) && rings.includes(`R${i}`)) {sum+=1;}}return sum;};console.log(countPoints(rings));