tjeastmond

/**
 *       10
 *      /  \
 *     4    17
 *    / \   / \
 *   1   9 12  18
 *  /
 * 22
 */

tjeastmond

BFS & DFS Notes

Links

• Breadth-first search - Wikipedia
• Depth-first search - Wikipedia

Fundamentally a graph is a data structure which is characterized by nonlinearity for representing connections of vertices (or nodes) and edges. By definition:

A graph is a data structure which consists of a finite set of nodes (or vertices) with a set of edges connecting a pair of nodes (or vertices).

tjeastmond

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

tjeastmond

function log(msg) {
  console.log(msg);
}

tjeastmond

// reverse character array

const reverse = arr => {
  if (arr.length === 1) return arr;
  let left = 0;
  let right = arr.length - 1;
  while (left < right) {
    [arr[left], arr[right]] = [arr[right], arr[left]];
    left++;
    right--;

tjeastmond

// quicksort

const quicksort = (arr, left = 0, right = arr.length - 1) => {
  if (left >= right) return;
  const pivot = arr[Math.floor((left + right) / 2)];
  const index = partition(arr, left, right, pivot);
  quicksort(arr, left, index - 1);
  quicksort(arr, index, right);
  return arr;
};

tjeastmond

/**
 * Simple mergesort exercise
 */

const mergeSort = unsortedArray => {
  if (unsortedArray.length <= 1) return unsortedArray;
  const middle = Math.floor(unsortedArray.length / 2);
  const left = unsortedArray.slice(0, middle);
  const right = unsortedArray.slice(middle);
  return merge(mergeSort(left), mergeSort(right));

tjeastmond

function getNames(person) {
  const names = [];
  names.push(person.name);
  person.children.forEach(child => names.push(...getNames(child)));
  return names;
}

const people = {
  name: "Robin",
  children: [

tjeastmond

function head() {
  console.log("HEAD");
  /* Some more logic that goes down here then will return function */

  return function body(arg) {
    console.log(arg);
    function inner() {
      console.log("INNER METHOD");
    }
    // return "SOMETHING USEFUL";

tjeastmond

var memoizer = function(memo, func) {
	var recur = function(n) {
		var result = memo[n];
		if (typeof result !== 'number') {
			result = func(recur, n);
			memo[n] = result;
		}
		return result;
	};
	return recur;