Garmelon/advent-of-code
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

[hs] Solve 2020_12 part 2

Browse source
This commit is contained in:
Joscha 2020-12-12 12:04:01 +00:00
parent c74894bc98
commit 92f43dea77
1 changed files with 33 additions and 33 deletions
Download patch file Download diff file Expand all files Collapse all files

66
hs/src/Aoc/Y2020/D12.hs
View file

@ -5,7 +5,6 @@ module Aoc.Y2020.D12
) where
import Data.Foldable
import Data.List
import Aoc.Day
import Aoc.Parse
@ -13,14 +12,11 @@ import Aoc.Parse
data Pos = Pos Int Int
deriving (Show)
data Dir = North | East | South | West
deriving (Show)
data Rot = RLeft | RRight | RFlip
deriving (Show)
data Move
= MTranslate Dir Int
= MTranslate Pos Int
| MForward Int
| MRotate Rot
deriving (Show)
@ -31,7 +27,11 @@ parser = manyLines
<|> (MForward <$> (char 'F' *> decimal))
<|> (MRotate <$> pRot)
where
pDir = foldr1 (<|>) [North <$ char 'N', East <$ char 'E', South <$ char 'S', West <$ char 'W']
pDir = foldr1 (<|>) [ Pos 0 (-1) <$ char 'N'
, Pos 1 0 <$ char 'E'
, Pos 0 1 <$ char 'S'
, Pos (-1) 0 <$ char 'W'
]
pRot = foldr1 (<|>) [ RLeft <$ (string "L90" <|> string "R270")
, RRight <$ (string "L270" <|> string "R90")
, RFlip <$ (string "L180" <|> string "R180")
@ -40,45 +40,45 @@ parser = manyLines
add :: Pos -> Pos -> Pos
add (Pos x1 y1) (Pos x2 y2) = Pos (x1 + x2) (y1 + y2)
mul :: Int -> Pos -> Pos
mul a (Pos x y) = Pos (a * x) (a * y)
manhattan :: Pos -> Int
manhattan (Pos x y) = abs x + abs y
dirToPos :: Dir -> Int -> Pos
dirToPos North d = Pos 0 (-d)
dirToPos East d = Pos d 0
dirToPos South d = Pos 0 d
dirToPos West d = Pos (-d) 0
rotate :: Rot -> Pos -> Pos
rotate RRight (Pos x y) = Pos (-y) x
rotate RLeft (Pos x y) = Pos y (-x)
rotate RFlip (Pos x y) = Pos (-x) (-y)
rotate :: Rot -> Dir -> Dir
rotate RRight North = East
rotate RRight East = South
rotate RRight South = West
rotate RRight West = North
rotate RLeft North = West
rotate RLeft East = North
rotate RLeft South = East
rotate RLeft West = South
rotate RFlip North = South
rotate RFlip East = West
rotate RFlip South = North
rotate RFlip West = East
data State = State Pos Dir
data State1 = State1 Pos Pos -- Ship, direction
deriving (Show)
step :: Move -> State -> State
step (MTranslate dir steps) (State spos sdir) = State (add spos $ dirToPos dir steps) sdir
step (MForward steps) (State spos sdir) = State (add spos $ dirToPos sdir steps) sdir
step (MRotate rot) (State spos sdir) = State spos (rotate rot sdir)
step1 :: Move -> State1 -> State1
step1 (MTranslate dir steps) (State1 spos sdir) = State1 (add spos $ mul steps dir) sdir
step1 (MForward steps) (State1 spos sdir) = State1 (add spos $ mul steps sdir) sdir
step1 (MRotate rot) (State1 spos sdir) = State1 spos (rotate rot sdir)
run :: [Move] -> State
run moves = foldr (flip (.) . step) id moves $ State (Pos 0 0) East
data State2 = State2 Pos Pos -- Ship, waypoint
deriving (Show)
step2 :: Move -> State2 -> State2
step2 (MTranslate dir steps) (State2 spos wp) = State2 spos (add wp $ mul steps dir)
step2 (MForward steps) (State2 spos wp) = State2 (add spos $ mul steps wp) wp
step2 (MRotate rot) (State2 spos wp) = State2 spos (rotate rot wp)
solver :: [Move] -> IO ()
solver moves = do
putStrLn ">> Part 1"
let (State pos1 _) = run moves
let initialState1 = State1 (Pos 0 0) (Pos 1 0)
(State1 pos1 _) = foldl' (flip step1) initialState1 moves
print $ manhattan pos1
putStrLn ""
putStrLn ">> Part 2"
let initialState2 = State2 (Pos 0 0) (Pos 10 (-1))
(State2 pos2 _) = foldl' (flip step2) initialState2 moves
print $ manhattan pos2
day :: Day
day = dayParse parser solver