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module Main where
import Data.Foldable (Foldable (foldl'))
import Utils
toDelta :: (String, Int) -> (Int, Int)
toDelta ("up", n) = (0, - n)
toDelta ("down", n) = (0, n)
toDelta ("forward", n) = (n, 0)
toDelta x = error $ "invalid instruction: " ++ show x
e1 :: [(String, Int)] -> Int
e1 =
map toDelta
.> foldl' (\(ax, ay) (x, y) -> (ax + x, ay + y)) (0, 0)
.> uncurry (*)
e2 :: [(String, Int)] -> Int
e2 =
map toDelta
.> foldl' (\(ax, ay, aaim) (x, aim) -> (ax + x, ay + aaim * x, aaim + aim)) (0, 0, 0)
.> \(x, y, _) -> x * y
main :: IO ()
main =
do
contents <- getContents
let input =
contents
$> lines
.> map words
.> map (\[x, y] -> (x, read y))
e1 input $> print
e2 input $> print
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