MichaelWalker-git

// Simple problems to solve using the native .reduce and .map array methods. Each of these problems can be solved in many
// different ways, but try to solve them using the requested higher order function.

// MAP

// Write a function capitalize that takes a string and uses .map to return the same string in all caps. 
// ex. capitalize('whoop') // => 'WHOOP'
// ex. capitalize('oh hey gurl') // => "OH HEY GURL"
var capitalize = function(string){
  // code code code!

MichaelWalker-git

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be a both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth. It also will be available as a gist on Github for everyone to edit and add to.

Data Structure Basics

###Array ####Definition:

• Stores data elements based on an sequential, most commonly 0 based, index.
• Based on tuples from set theory.

MichaelWalker-git

function tapeEquilibrium(A) {
    var p, i;
    var leftSum = 0, rightSum = 0;
    var totalSum = 0;
    var lastMin, currentMin;
    var leng = A.length;
    
    if (leng == 2) { return Math.abs(A[0] - A[1]); }
    if (leng == 1) { return Math.abs(A[0]); }
    //edge cases where the length is 1 or 2

MichaelWalker-git

function solution(A) {
        var min = 1;
        A.sort(function(a,b){
           // Sort the array explicit way
           return a - b; 
        });

        for (var i in A) {
            if (A[i] > -1 && A[i] == min) {
                min++;

MichaelWalker-git

/*
  You are given N counters, initially set to 0, and you have two possible operations on them:
  
  • increase(X) − counter X is increased by 1,
  • max counter − all counters are set to the maximum value of any counter.
  
  A non-empty zero-indexed array A of M integers is given. This array represents consecutive operations:
  
  • if A[K] = X, such that 1 ≤ X ≤ N, then operation K is increase(X),
  • if A[K] = N + 1 then operation K is max counter.

MichaelWalker-git

function prefixSums(A){
  var leng = A.length;
  p = [0] * (leng +1);
  for(var i = 0; i< leng+1; i++){
    P[i] = P[i-1] + A[i-1];
  }
  return P;
}

MichaelWalker-git

Given non empty, zero indexed array (A) 
A has n integers (1 < n < 100000) 

A represents number of mushrooms growing in a consecutive spots along the road

Given integers k and m

k = spot on the road and m = number of moves

In one move, she moves to an adjacent spot

MichaelWalker-git

function solution(X, A) {
    // write your code in JavaScript (Node.js 0.12)
    var count = new Array(X);
    
    for ( var i=0; i < A.length; i++) {
        var info = {
            minute : i,
            count : 1
        };

MichaelWalker-git

function oneArray(arr) {
  return arr.reduce(function (first, next) {
    return first.concat(Array.isArray(next) ? oneArray(next) : next);
  }, []);
}

oneArray([[1,2,[3]],4]);

MichaelWalker-git

let map = new Map();
map.set("a", 1);
map.set("b", 2);
map.set("c", 3);

let obj = Array.from(map).reduce((obj, [key, value]) => (
  Object.assign(obj, { [key]: value }) // Be careful! Maps can have non-String keys; object literals can't.
), {});

console.log(obj); // => { a: 1, b: 2, c: 3 }