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Day 22 - minor refactoring

This commit is contained in:
Jonathan Chan 2017-12-22 13:06:37 -08:00
parent 22aad7dd66
commit b7e9013d09
2 changed files with 21 additions and 31 deletions
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12
22a.hs
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@ -6,9 +6,8 @@ type State = (Grid, (Int, Int), Direction, Int)
(%) = mod
changeDirection :: Char -> Direction -> Direction
changeDirection c = case c of
'#' -> toEnum . (%4) . (+1) . fromEnum
'.' -> toEnum . (%4) . (+3) . fromEnum
changeDirection c =
toEnum . (%4) . (+ if c == '#' then 1 else 3) . fromEnum
incrementPosition :: Direction -> (Int, Int) -> (Int, Int)
incrementPosition dir (x, y) = case dir of
@ -23,7 +22,7 @@ nextState (grid, pos, dir, count) =
newDir = changeDirection currNode dir
newGrid = insert pos (if currNode == '.' then '#' else '.') grid
newPos = incrementPosition newDir pos
newCount = count + if currNode == '.' then 1 else 0
newCount = count + fromEnum (currNode == '.')
in (newGrid, newPos, newDir, newCount)
parseRow :: (Int, [(Int, Char)]) -> Grid -> Grid
@ -31,7 +30,6 @@ parseRow (y, xs) grid = foldr (\(x, c) currGrid -> insert (x, y) c currGrid) gri
main :: IO ()
main = do
input <- readFile "22.txt"
let grid = foldr parseRow empty $ zip [-12..12] . map (zip [-12..12]) . lines $ input
(_, _, _, count) = iterate nextState (grid, (0, 0), North, 0) !! 10000
grid <- foldr parseRow empty . zip [-12..12] . map (zip [-12..12]) . lines <$> readFile "22.txt"
let (_, _, _, count) = iterate nextState (grid, (0, 0), North, 0) !! 10000
print $ count

40
22b.hs
View File

@ -1,24 +1,14 @@
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE BangPatterns, ScopedTypeVariables #-}
import Data.HashMap.Strict (HashMap, lookupDefault, insert, empty)
data Direction = North | East | South | West deriving Enum
type Grid = HashMap (Int, Int) Char
data Direction = North | East | South | West deriving (Bounded, Enum)
data Node = Weakened | Infected | Flagged | Clean deriving (Bounded, Enum, Eq)
type Grid = HashMap (Int, Int) Node
type State = (Grid, (Int, Int), Direction, Int)
(%) = mod
(%) = mod; infixl 5 %
changeDirection :: Char -> Direction -> Direction
changeDirection c = case c of
'#' -> toEnum . (%4) . (+1) . fromEnum
'F' -> toEnum . (%4) . (+2) . fromEnum
'.' -> toEnum . (%4) . (+3) . fromEnum
'W' -> id
changeNode :: Char -> Char
changeNode c = case c of
'.' -> 'W'
'W' -> '#'
'#' -> 'F'
'F' -> '.'
succn :: forall a. (Bounded a, Enum a) => Int -> a -> a
succn n = toEnum . (% 1 + fromEnum (maxBound :: a)) . (+ n) . fromEnum
incrementPosition :: Direction -> (Int, Int) -> (Int, Int)
incrementPosition dir (x, y) = case dir of
@ -29,11 +19,11 @@ incrementPosition dir (x, y) = case dir of
nextState :: State -> State
nextState (grid, pos, dir, count) =
let currNode = lookupDefault '.' pos grid
newDir = changeDirection currNode dir
newGrid = insert pos (changeNode currNode) grid
let currNode = lookupDefault Clean pos grid
newDir = succn (fromEnum currNode) dir
newGrid = insert pos (succn 1 currNode) grid
newPos = incrementPosition newDir pos
!newCount = count + if currNode == 'W' then 1 else 0
!newCount = count + fromEnum (currNode == Weakened)
in (newGrid, newPos, newDir, newCount)
stricterate :: Int -> State -> Int
@ -41,10 +31,12 @@ stricterate 0 (_, _, _, count) = count
stricterate n state = let !next = nextState state in stricterate (n-1) next
parseRow :: (Int, [(Int, Char)]) -> Grid -> Grid
parseRow (y, xs) grid = foldr (\(x, c) currGrid -> insert (x, y) c currGrid) grid xs
parseRow (y, xs) grid = foldr (\(x, c) currGrid -> insert (x, y) (charToEnum c) currGrid) grid xs
where charToEnum c = case c of
'.' -> Clean
'#' -> Infected
main :: IO ()
main = do
input <- readFile "22.txt"
let grid = foldr parseRow empty $ zip [-12..12] . map (zip [-12..12]) . lines $ input
grid <- foldr parseRow empty . zip [-12..12] . map (zip [-12..12]) . lines <$> readFile "22.txt"
print $ stricterate 10000000 (grid, (0, 0), North, 0)