AdventOfCode2019

Aoc1.hs

{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE DerivingVia #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}

module Aoc1 where

import Data.Foldable
import Data.Monoid (Sum(..))
import Data.Ratio 

---- Excercise 1

newtype Mass = Mass Integer
  deriving stock (Eq, Ord, Show)
  deriving Semigroup via (Sum Integer)
  deriving Monoid via (Sum Integer)

newtype Fuel = Fuel Mass 
  deriving stock (Eq, Ord, Show)
  deriving newtype Semigroup
  deriving newtype Monoid

massCost :: Mass -> Fuel
massCost (Mass i) = Fuel (Mass (floor (i % 3) - 2))

-- 3471229
answer1 :: Fuel
answer1 = foldl' mappend mempty (fmap massCost input)

---- Exercise 2

fuelCost :: Fuel -> Fuel
fuelCost (Fuel m0) =
  case massCost m0 of
    f1 | f1 > mempty -> mappend f1 (fuelCost f1)
       | otherwise -> mempty
       
-- 5203967
answer2 :: Fuel
answer2 = foldl' mappend mempty (fmap (fuelCost . Fuel) input)

input :: [Mass]
input = fmap Mass
 [129192,
  58561,
  57267,
  95382,
  84995,
  127372,
  93598,
  97264,
  138550,
  79327,
  135661,
  139468,
  108860,
  149642,
  72123,
  128333,
  69002,
  98450,
  86267,
  70171,
  101333,
  79822,
  142539,
  142743,
  51371,
  111381,
  62073,
  72210,
  125168,
  135952,
  131060,
  121842,
  88234,
  146774,
  136571,
  126719,
  50644,
  75696,
  51195,
  77171,
  118052,
  83691,
  133779,
  149814,
  64847,
  110697,
  92695,
  59453,
  139517,
  129487,
  79271,
  97896,
  146987,
  149822,
  71866,
  90797,
  104732,
  54997,
  50139,
  134115,
  133017,
  144979,
  89428,
  124750,
  91833,
  57252,
  67195,
  121624,
  102706,
  138245,
  127700,
  124098,
  110382,
  121557,
  103613,
  133576,
  122801,
  112306,
  120203,
  134696,
  76129,
  84576,
  80854,
  147237,
  71025,
  127513,
  143631,
  125090,
  115698,
  57979,
  84880,
  120177,
  147389,
  88380,
  114688,
  56355,
  126265,
  58220,
  63523,
  130179]