39 lines
956 B
Haskell
39 lines
956 B
Haskell
-- https://adventofcode.com/2024/day/1
|
|
|
|
import Data.List
|
|
import GHC.IO
|
|
|
|
input :: FilePath
|
|
input = "src/advent_of_code/2024/1.input"
|
|
|
|
entries :: ([Int], [Int])
|
|
entries = unzip $ map parse' $ unsafePerformIO $ lines <$> readFile input
|
|
|
|
main :: IO ()
|
|
main = do
|
|
entries <- lines <$> readFile input
|
|
print "Advent of Code 2024 - Day 1"
|
|
|
|
print $ "Part 1: " <> show (solveP1 $ unzip $ map parse' entries)
|
|
print $ "Part 2: " <> show (solveP2 $ unzip $ map parse' entries)
|
|
|
|
parse' :: String -> (Int, Int)
|
|
parse' str = (read l, read r)
|
|
where
|
|
l = take' str
|
|
r = reverse $ take' $ reverse str
|
|
take' = takeWhile (/= ' ')
|
|
|
|
solveP1 :: ([Int], [Int]) -> Int
|
|
solveP1 (as, bs) = sum $ zipWith (\i j -> abs (i - j)) as' bs'
|
|
where
|
|
as' = sort as
|
|
bs' = sort bs
|
|
|
|
solveP2 :: ([Int], [Int]) -> Int
|
|
solveP2 (as, bs) = sum $ zipWith (*) as (map (f bs) as)
|
|
where
|
|
f :: [Int] -> Int -> Int
|
|
f bs a = length $ elemIndices a bs
|
|
|