Add day 13

Author: vekerdyb

day13/Day13Part1Part2.hs

@@ -0,0 +1,65 @@
+import Data.List
+import Data.Ix
+
+splitOn :: Char -> String -> (String, String)
+splitOn separator str = (takeWhile (/= separator) str, tail $ dropWhile (/= separator) str)
+
+unique :: Eq a => [a] -> [a]
+unique [] = []
+unique (x:xs) = x:unique (filter ((/=) x) xs)
+
+foldUpCoords :: Int -> (Int, Int) -> (Int, Int)
+foldUpCoords foldLine (x, y)
+    | foldLine >= y = (x, y)
+    | otherwise = (x, foldLine - (y - foldLine))
+
+foldLeftCoords :: Int -> (Int, Int) -> (Int, Int)
+foldLeftCoords foldLine (x, y)
+    | foldLine >= x = (x, y)
+    | otherwise = (foldLine - (x - foldLine), y)
+
+foldCoords :: Char -> Int -> (Int, Int) -> (Int, Int)
+foldCoords axis
+    | axis == 'x' = foldLeftCoords
+    | otherwise = foldUpCoords
+
+foldOne :: (Char, Int) -> [(Int, Int)] -> [(Int, Int)]
+foldOne (axis, foldLine) listCoords = unique $ filter (\(x, y) -> x >= 0 && y >= 0)
+                                          [ foldCoords axis foldLine coords | coords <- listCoords ]
+
+foldAll :: [(Char, Int)] -> [(Int, Int)] -> [(Int, Int)]
+foldAll [] listCoords = listCoords
+foldAll (f:folds) listCoords = foldAll folds (foldOne f listCoords)
+
+-- utils for pretty print
+maxCoords_ :: Int -> Int -> [(Int, Int)] -> (Int, Int)
+maxCoords_ maxX maxY [] = ( maxX , maxY )
+maxCoords_ maxX maxY ((x, y):coords)= maxCoords_ (maximum [ maxX, x ]) (maximum [maxY , y ]) coords
+
+maxCoords :: [(Int, Int)] -> (Int, Int)
+maxCoords coords = maxCoords_ 0 0 coords
+
+allCoords :: [(Int, Int)] -> [(Int, Int)]
+allCoords coords = [(y, x) | (x, y) <- range ((0,0), (snd $ maxCoords coords, fst $ maxCoords coords))]
+
+chunk :: Int -> [a] -> [[a]]
+chunk _ [] = []
+chunk n l
+  | n > 0 = (take n l) : (chunk n (drop n l))
+  | otherwise = error "Negative or zero n"
+
+printMatrix :: [(Int, Int)] -> IO ()
+printMatrix coords = mapM_ putStrLn $ chunk ((fst $ maxCoords coords) + 1)
+                           [if c `elem` coords then '#' else '.' | c <- allCoords coords]
+
+main = do
+    ls <- readFile "day13/input.txt"
+    let coords = map (\c -> (read $ (fst c)::Int, read $ (snd c)::Int))
+                    . map (splitOn ',')
+                    . takeWhile (/="") $ lines ls
+    let folds = map (\f -> (head $ fst f, read $ (snd f)::Int))
+                    . map (splitOn '=' . drop 11)
+                    . drop (length coords + 1) $ lines ls
+    putStrLn $ "Part 1: " ++ show (length $ foldOne (head $ folds) coords)
+    putStrLn $ "Part 2:"
+    printMatrix $ foldAll folds coords