JorgeCastilloPrz

fun sumOfFactors(number: Int) = factorsOf(number).sum()

fun factorsOf(number: Int) = (1 to number).toList().filter { isFactor(number, it) }

fun isFactor(number: Int, potential: Int) = number % potential == 0

JorgeCastilloPrz

class FactorCalculator {
    val sumCache = hashMapOf<Int, Int>()
    val factorCache = hashMapOf<Int, List<Int>>()

    fun sumOfFactors(number: Int) = sumCache.getOrPut(number, {
        factorsOf(number).sum()
    })

    fun isFactor(number: Int, potential: Int) = number % potential == 0

JorgeCastilloPrz

tailrec fun <T> filter(l: List<T>, res: List<T>, f: (T) -> Boolean): List<T> {
    if (l.isEmpty()) {
        return res
    } else {
        return filter(l.tail(), if (f(l.head())) { res + listOf(l.head())} else { res }, f)
    }
}

JorgeCastilloPrz

fun <T> filter(l: List<T>, res: List<T>, f: (T) -> Boolean): List<T> {
    if (l.isEmpty()) {
        return res
    } else {
        return filter(l.tail(), if (f(l.head())) { res + listOf(l.head())} else { res }, f)
    }
}

JorgeCastilloPrz

fun <T> List<T>.tail() = drop(1)
fun <T> List<T>.head() = first()

fun <T> filter(l: List<T>, f: (T) -> Boolean): List<T> {
    if (l.isEmpty()) {
        return listOf()
    } else {
        return if (f(l.head())) {
            listOf(l.head()) + filter(l.tail(), f)
        } else {

JorgeCastilloPrz

fun <T> filter(l: List<T>, f: (T) -> Boolean): MutableList<T> {
    val res = mutableListOf<T>()
    l.forEach { if (f(it)) { res += it  } }
    return res
}

JorgeCastilloPrz

override fun getAll() = listOf(SuperHero("IronMan"), SuperHero("Spider-Man"),
      SuperHero("Batman"), SuperHero("Goku"), SuperHero("Vegeta"), SuperHero("SuperMan"),
      SuperHero("Ant-Man"), SuperHero("Krilin"), SuperHero("Super Mario"), 
      SuperHero("Wolverine"), SuperHero("Massacre"), SuperHero("Jake Wharton"), 
      SuperHero("Jesus Christ"), SuperHero("Donald Trump (villain)"))

JorgeCastilloPrz

fun getHeroes() = Reader<GetHeroesContext, List<SuperHero>> {
  it.heroesDataSources[0].getAll()
}

JorgeCastilloPrz

fun getSuperHeroes(): Reader<GetHeroesContext, List<SuperHero>> =
    Reader.ask<GetHeroesContext>().flatMap { ctx -> ctx.heroesRepository.getHeroes() }

JorgeCastilloPrz

fun getSuperHeroes(): Reader<GetHeroesContext, Unit> = 
  Reader.ask<GetHeroesContext>().flatMap {
    ctx -> ctx.getSuperHeroesInteractor.getSuperHeroes().map {
      if (it.isEmpty()) ctx.view.showHeroesNotFoundError()
      else ctx.view.drawHeroes(it.map { SuperHeroViewModel(it.name) })
    }
}