Nicolas Cavallo nicocavallo

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.

Background

While Kotlin is not a pure functional language, it provides Higher order functions and an expressive way of writing programs vs statements provided by imperative languages like Java.

Functions

Function declaration


	lazy val root = (project in file("."))
	.enablePlugins(PlayScala, SbtLiquibase, BuildInfoPlugin)
	.settings(
	buildInfoKeys := Seq[BuildInfoKey](name, version, scalaVersion, sbtVersion,
	"buildNumber" -> Option(System.getenv("BUILD_NUMBER")).getOrElse("n/a"),
	"gitCommit" -> Option(System.getenv("GIT_COMMIT")).getOrElse("n/a"),
	"gitBranch" -> Option(System.getenv("GIT_BRANCH")).getOrElse("n/a")
	),
	buildInfoPackage := "picsolve.jenkins.metadata",

	param(
	$confPath = "./conf.txt"
	)

	while (1)
	{

	$props = convertfrom-stringdata (get-content -path $confPath -raw)

	$period = [convert]::ToInt32($props.'app.interval', 10)

	package nicocavallo.contentful

	import java.time.ZonedDateTime

	import com.contentful.java.cda._
	import com.typesafe.config.Config
	import org.reactivestreams.{Subscriber, Subscription}

	import scala.concurrent.{Future, Promise}
	import scala.language.postfixOps

	import cats._
	import cats.data.Validated.{Invalid, Valid}
	import cats.data.{ValidatedNel, _}
	import cats.implicits._

	case class Person(name: String, jobTitle: String, age: Int)
	case class Error(msg: String)

	type ValidationResult[T] = ValidatedNel[Error,T]

	import javax.crypto.Mac
	import javax.crypto.spec.SecretKeySpec

	import org.apache.commons.codec.binary.Hex

	val sharedSecret = "whsec_A2EdfajGiGHx9jFmkP7ia6j25VXh9IWV"

	val payload = "{\n \"id\": \"evt_YEEz4JGN6UwGkCjdqr7wfPqL\",\n \"object\": \"event\",\n \"api_version\": \"2017-06-05\",\n \"created\": 1509023721,\n \"data\": {\n \"object\": {\n \"id\": \"my-first-test-plan\",\n \"object\": \"plan\",\n \"amount\": 599,\n \"created\": 1509023721,\n \"currency\": \"gbp\",\n \"interval\": \"month\",\n \"interval_count\": 1,\n \"livemode\": false,\n \"metadata\": {\n },\n \"name\": \"My first test plan\",\n \"statement_descriptor\": \"My first test plan\",\n \"trial_period_days\": 31\n }\n },\n \"livemode\": false,\n \"pending_webhooks\": 1,\n \"request\": {\n \"id\": \"req_6UwGkCjdqr7wfPqLAq\",\n \"idempotency_key\": null\n },\n \"type\": \"plan.created\"\n}"
	val header = "t=1509023726,v1=e786c1d46f2fa3bbd57cf974e89533ecb89b

	[
	{"isoCode": "AT", "name": "Austria"},
	{"isoCode": "BE", "name": "Belgium"},
	{"isoCode": "BG", "name": "Bulgaria"},
	{"isoCode": "HR", "name": "Croatia"},
	{"isoCode": "CY", "name": "Cyprus"},
	{"isoCode": "CZ", "name": "Czech Republic"},
	{"isoCode": "DK", "name": "Denmark"},
	{"isoCode": "EE", "name": "Estonia"},
	{"isoCode": "FI", "name": "Finland"},