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const primes = num => {let arr = Array.from({ length: num - 1 }).map((x, i) => i + 2),sqroot = Math.floor(Math.sqrt(num)),numsTillSqroot = Array.from({ length: sqroot - 1 }).map((x, i) => i + 2);numsTillSqroot.forEach(x => (arr = arr.filter(y => y % x !== 0 || y === x)));return arr;};primes(10); // [2, 3, 5, 7]
/*** @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]}}}};
const union = (...arr) => [...new Set(arr.flat())];// Exampleunion([1, 2], [2, 3], [3]); // [1, 2, 3]
const heapsort = arr => {const a = [...arr];let l = a.length;const heapify = (a, i) => {const left = 2 * i + 1;const right = 2 * i + 2;let max = i;if (left < l && a[left] > a[max]) max = left;if (right < l && a[right] > a[max]) max = right;if (max !== i) {[a[max], a[i]] = [a[i], a[max]];heapify(a, max);}};for (let i = Math.floor(l / 2); i >= 0; i -= 1) heapify(a, i);for (i = a.length - 1; i > 0; i--) {[a[0], a[i]] = [a[i], a[0]];l--;heapify(a, 0);}return a;};heapsort([6, 3, 4, 1]); // [1, 3, 4, 6]
const express = require('express')const app = express()const port = 3000app.get('/', (req, res) => {res.send('Hello World!')})app.listen(port, () => {console.log(`Example app listening on port ${port}`)})
// There are n rings and each ring is either red, green, or blue. The rings are distributed across ten rods labeled from 0 to 9.// You are given a string rings of length 2n that describes the n rings that are placed onto the rods. Every two characters in rings forms a color-position pair that is used to describe each ring where:// The first character of the ith pair denotes the ith ring's color ('R', 'G', 'B').// The second character of the ith pair denotes the rod that the ith ring is placed on ('0' to '9').// For example, "R3G2B1" describes n == 3 rings: a red ring placed onto the rod labeled 3, a green ring placed onto the rod labeled 2, and a blue ring placed onto the rod labeled 1.// Return the number of rods that have all three colors of rings on them.let rings = "B0B6G0R6R0R6G9";var countPoints = function(rings) {let sum = 0;// Always 10 Rodsfor (let i = 0; i < 10; i++) {if (rings.includes(`B${i}`) && rings.includes(`G${i}`) && rings.includes(`R${i}`)) {sum+=1;}}return sum;};console.log(countPoints(rings));