jasonwaters

const noop = () => void 0;

function Covenant(fn) {
    this.resolver = fn;
    this.thenCallback = noop;
    this.catchCallback = noop;

    this.resolver((...args) => {
        this.thenCallback(...args);
    }, () => {

jasonwaters

function jayquery(selector) {
    const elements = document.querySelectorAll(selector);

    return {
        bgcolor: function(value) {
            elements.forEach(element => element.style.background = value);
            return this;
        },
        text: function(value) {
            elements.forEach(element => element.innerText = value);

jasonwaters

function randy() {
    return Math.random();
}

function smoke() {
    return "poof";
}

function depend(dependencies, fn) {
    fn.apply(null, dependencies.map(dep => window[dep]));

jasonwaters

function permute(arr, permutation=[], permutations=[]) {

  if(arr.length === 0) {
    permutations.push(permutation);
  }else {
    arr.forEach(item => {
      permute(arr.filter(value => value != item), permutation.concat(item), permutations);
    });
  }
  return permutations;

jasonwaters

//https://www.hackerrank.com/challenges/ctci-recursive-staircase

function stairStepper(stepSizes) {
    let answers = [1,1];
    return function(numSteps) {
        if(numSteps < 0) {
            return 0;
        }else if(typeof answers[numSteps] === 'undefined') {
            answers[numSteps] = stepSizes.reduce((totalSteps, stepSize) => totalSteps + stairCombinations(numSteps-stepSize), 0);
        }

jasonwaters

// A prime number is a natural number that has exactly two distinct natural number divisors: 1 and itself.

const isPrime = (function () {
    let primes = {};
    let notPrimes = {};

    return function (number) {
        if(primes[number]) return true;
        if(number === 1 || notPrimes[number]) return false;

jasonwaters

function merge(arrA, arrB) {
    let idxA=0, idxB=0, result=[];

    while(idxA < arrA.length || idxB < arrB.length) {

        if(idxB === arrB.length || arrA[idxA] <= arrB[idxB]) {
            result.push(arrA[idxA]);
            idxA++;
        }else if(idxA === arrA.length || arrB[idxB] <= arrA[idxA]) {
            result.push(arrB[idxB]);

jasonwaters

// https://www.hackerrank.com/challenges/ctci-find-the-running-median

let input = `6
12
4
5
3
8
7`;

jasonwaters

// https://www.hackerrank.com/challenges/ctci-contacts


function Trie() {
    this.data = {};
}

Trie.prototype.process = function(op, str) {
    if(op === 'add') {
        let data = this.data;

jasonwaters

// https://www.hackerrank.com/challenges/ctci-ice-cream-parlor
// find 2 distinct flavors that would take up all of the money m

// for each trip print the id numbers of the two types of ice cream
// some ice creams may have the same price


function purchase(indexed, product) {
    let result = Object.assign({}, indexed);