albertywu

class ProfitCalculator {
  
  constructor(prices) {
    this.prices = prices
  }

  // implementation 1 uses standard for-loop
  getMaxProfit() {
    let maxProfit = 0
    let minPrice = this.prices[0]

albertywu

const returnedDrones = {}

function dispatchDrones(drones) {
  drones.forEach(d => {
    droneId = d.dispatch() // droneId contains a random but unique id
    returnedDrones[droneId] = false
  }
}

// run this function at end of day

albertywu

// assumes the passed-in array contains a single non-duplicate. Finds the non-duplicate.
// O(3n) = O(n) runtime
findNonduplicate = (numbers) => {
  const count = {}

  // N
  numbers.forEach(n => count[n] = count[n] ? count[n] + 1 : 1)

  return (Object
    .keys(count)

albertywu

class IntWithPow(val i: Int) {
  def pow(n: Int) = Math.pow(i, n).toInt
}

implicit def intToInt(i: Int) = new IntWithPow(i)

// z = ax + by + c
type LinSolution = (Int, Int, Int)

val testRange = 0 to 5

albertywu

// given: Array.prototype.forEach, derive:
// 1. reduce
// 2. concat
// 3. map
// 4. filter
// 5. flatten
// 6. flatMap

const reduce = (xs, f, z) => {
  var acc = z

albertywu

// The "favoriteNumber" key returns a value that Int | String. Normalize the response.

val json1 = Json.parse(
  """
    |{
    |"name": "Albert",
    |"age": 32,
    |"favoriteNumber": 42
    |}
  """.stripMargin)

albertywu

# add to your ~/.bash_profile or startup script
jazzygif () { ffmpeg -i "$1" -vf scale=-1:-1 -r 10 -f image2pipe -vcodec ppm - | convert -delay 5 -layers Optimize -loop 0 - "$2"; }

# here's how you run it (assumes that pug.mp4 is in current working directory)
jazzygif pug.mp4 pug.gif

# or, specify paths to files
jazzygif ~/Desktop/pug.mp4 ~/Documents/pugs/pug.gif

albertywu

#!/usr/bin/env bash
set -ex

PROJECT=$1
mkdir $PROJECT && cd $PROJECT
yarn init -y
yarn add -D @babel/cli @babel/core @babel/preset-env @babel/preset-flow
yarn add @babel/polyfill
echo "{\"presets\": [\"@babel/preset-env\", \"@babel/preset-flow\"]}" | jq >> .babelrc
mkdir src

albertywu

type Methods = 'get' | 'post';

interface Req {
  data: object;
  method: Methods;
  url: string;
  foo?: number
}

class Req implements Req {

albertywu

/*
Notes:

DataSource
  - a stream of data
    - hasNext(), getNext()
  - examples: Location, Transactions, Contacts, ...
  - an algorithm's output is a DataSource

Transaction