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Refactored Day 6 for clarity.

This commit is contained in:
Jonathan Chan 2017-12-12 09:28:52 -08:00
parent 2b209648d5
commit cf61ef2a44
1 changed files with 14 additions and 9 deletions
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23
6.hs
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@ -3,11 +3,15 @@ import Data.HashMap
import Data.Sequence
type Bank = Seq Int
type Config = (Bank, Data.HashMap.Map [Int] Int)
type HashableBank = [Int]
type Config = (Bank, Data.HashMap.Map HashableBank Int)
(%) :: Int -> Int -> Int
(%) = mod
(//) :: Int -> Int -> Int
(//) = div
getMaxMem :: Bank -> (Int, Int)
getMaxMem bank =
foldlWithIndex (\(currIndex, currMax) index value -> if value > currMax then (index, value) else (currIndex, currMax)) (0, 0) bank
@ -17,18 +21,19 @@ nextBank bank =
let len = Data.Sequence.length bank
(index, value) = getMaxMem bank
zeroedBank = Data.Sequence.update index 0 bank
mappedBank = fmap (+ value `div` len) zeroedBank
indicesToUpdate = fmap (% len) [(index + 1)..(index + value % len)]
mappedBank = fmap (+ value // len) zeroedBank
indicesToUpdate = fmap ((% len) . (+ index)) [1..value % len]
in mapWithIndex (\i v -> if i `elem` indicesToUpdate then v + 1 else v) mappedBank
cycles :: Int -> Config -> (Int, Int)
cycles count (prevBank, configs) =
let bank = nextBank prevBank
hashableBank = Data.Foldable.toList bank
in if member hashableBank configs
then (count + 1, (count + 1) - findWithDefault undefined hashableBank configs)
else cycles (count + 1) (bank, insert hashableBank (count + 1) configs)
cycles prevCount (prevBank, banks) =
let count = prevCount + 1
bank = nextBank prevBank
hashableBank = Data.Foldable.toList bank
in if member hashableBank banks
then (count, count - findWithDefault undefined hashableBank banks)
else cycles count (bank, insert hashableBank count banks)
main :: IO ()
main = do