Advent of Code 2024 - Day 1

src/advent_of_code/2024/1.hs

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+-- 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
+

src/advent_of_code/2024/1f.input

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+3   4
+4   3
+2   5
+1   3
+3   9
+3   3