WIP AOC 2022 & 2023

AOC2023/src/Day11.hs

@@ -0,0 +1,37 @@
+{-# LANGUAGE TupleSections #-}
+module Day11 (day11) where
+import Data.List (elemIndices)
+
+getRowsToExpand :: [String] -> [Int]
+getRowsToExpand input = filter (\i -> all (== '.') (input !! i)) [0..(length input - 1)]
+
+getColsToExpand :: [String] -> [Int]
+getColsToExpand input = filter (all (== '.') . byCol) [0..(length (head input) - 1)]
+  where byCol n = map (!! n) input
+
+getGalaxiesPos :: [String] -> [(Int, Int)]
+getGalaxiesPos input = concatMap getGalaxiesAtLine [0..(length input - 1)]
+  where getGalaxiesAtLine n = map (, n) (elemIndices '#' (input !! n))
+
+getPairs :: [a] -> [(a, a)]
+getPairs [] = []
+getPairs (h:t) = map (h,) t ++ getPairs t
+
+getDistance :: [Int] -> [Int] -> Int -> (Int, Int) -> (Int, Int) -> Int
+getDistance cols rows factor (x1, y1) (x2, y2) = abs (y2 - y1) + abs (x2 - x1) + ((rowsExpansion + colsExpansion) * factor)
+  where rowsExpansion = length $ filter (\i -> i > minimum [y1, y2] && i < maximum [y1, y2]) rows
+        colsExpansion = length $ filter (\i -> i > minimum [x1, x2] && i < maximum [x1, x2]) cols
+
+day11 :: IO ()
+day11 = do
+  putStrLn "AOC 2023 day 11"
+  input <- getContents
+  let input' = lines input
+  let colsToExpand = getColsToExpand input'
+  let rowsToExpand = getRowsToExpand input'
+  let galaxiesPos = getGalaxiesPos input'
+  let pairs = getPairs galaxiesPos
+  putStrLn "Part1"
+  print $ sum $ map (uncurry (getDistance colsToExpand rowsToExpand 1)) pairs
+  putStrLn "Part2"
+  print $ sum $ map (uncurry (getDistance colsToExpand rowsToExpand (1000000 - 1))) pairs