cleanup

code/src/05/Main.hs

@@ -3,19 +3,30 @@ module Main where
 import Data.List
 import Text.Parsec
 
+type Point = (Int,Int)
+data LinePoints =
+    Straight [Point]
+  | Diag [Point]
+
 main :: IO ()
 main = do
   raw <- getContents
-  putStrLn $ "day5a: " ++ show (solveA $ validate $ map (parse (lineP createSpots) []) $ lines raw)
-  putStrLn $ "day5b: " ++ show (solveB $ validate $ map (parse (lineP createSpots') []) $ lines raw)
+  let input = validate $ map (parse lineP []) $ lines raw
+  putStrLn $ "day5a: " ++ show (solve $ concatLP $ filter isStraight input)
+  putStrLn $ "day5b: " ++ show (solve $ concatLP input)
 
-validate :: [Either ParseError [(Int,Int)]] -> [(Int,Int)]
+concatLP :: [LinePoints] -> [Point]
+concatLP [] = []
+concatLP ((Straight ps):ls) = ps ++ (concatLP ls)
+concatLP ((Diag ps):ls) = ps ++ (concatLP ls)
+
+validate :: [Either ParseError a] -> [a]
 validate [] = []
 validate ((Left _):_) = error "invalid input"
-validate ((Right b):bs) = b ++ (validate bs)
+validate ((Right b):bs) = b:(validate bs)
 
-lineP :: ((Int,Int) -> (Int,Int) -> [(Int,Int)]) -> Parsec String () [(Int,Int)]
-lineP f = do
+lineP :: Parsec String () LinePoints
+lineP = do
   x1 <- many1 digit
   _ <- char ','
   y1 <- many1 digit
@@ -23,26 +34,20 @@ lineP f = do
   x2 <- many1 digit
   _ <- char ','
   y2 <- many1 digit
-  return $ f (read x1, read y1) (read x2, read y2)
+  return $ createSpots (read x1, read y1) (read x2, read y2)
 
 range :: Int -> Int -> [Int]
 range x y = [ i .. j ]
   where
     (i,j) = if x > y then (y,x) else (x,y)
 
-createSpots :: (Int,Int) -> (Int,Int) -> [(Int,Int)]
+createSpots :: Point -> Point -> LinePoints
 createSpots (x1,y1) (x2,y2)
-  | x1 == x2 = [ (x1,j) | j <- range y1 y2]
-  | y1 == y2 = [ (i,y1) | i <- range x1 x2]
-  | otherwise = []
+  | x1 == x2 = Straight [ (x1,j) | j <- range y1 y2]
+  | y1 == y2 = Straight [ (i,y1) | i <- range x1 x2]
+  | otherwise = Diag $ runDiag (x1,y1) (x2,y2)
 
-createSpots' :: (Int,Int) -> (Int,Int) -> [(Int,Int)]
-createSpots' (x1,y1) (x2,y2)
-  | x1 == x2 = [ (x1,j) | j <- range y1 y2]
-  | y1 == y2 = [ (i,y1) | i <- range x1 x2]
-  | otherwise = runDiag (x1,y1) (x2,y2)
-
-runDiag :: (Int,Int) -> (Int,Int) -> [(Int,Int)]
+runDiag :: Point -> Point -> [Point]
 runDiag (x1,y1) (x2,y2)
   | y1 < y2 =
     if x1 < x2
@@ -51,11 +56,10 @@ runDiag (x1,y1) (x2,y2)
   | otherwise =
     if x1 < x2
     then take (x2-x1+1) $ iterate dr (x2,y2)
-    else take (x1-x2+1) $ iterate ur (x1,y1)
+    else take (x1-x2+1) $ iterate dl (x2,y2)
   where
     dl (x,y) = (x+1,y+1)
     dr (x,y) = (x-1,y+1)
-    ur (x,y) = (x-1,y-1)
 
 rle :: Eq a => [a] -> [(Int,a)]
 rle xs = rle' $ zip (repeat 1) xs
@@ -67,8 +71,10 @@ rle' ((xv,xk):(yv,yk):xs) =
   else (xv,xk) : (rle' ((yv,yk):xs))
 rle' xs = xs
 
-solveA :: [(Int,Int)] -> Int
-solveA ps = length $ filter (\x -> (fst x) >= 2) $ rle $ sort ps
+isStraight :: LinePoints -> Bool
+isStraight (Straight _) = True
+isStraight _ = False
+
+solve :: [Point] -> Int
+solve ps = length $ filter (\x -> (fst x) >= 2) $ rle $ sort ps
 
-solveB :: [(Int,Int)] -> Int
-solveB ps = length $ filter (\x -> (fst x) >= 2) $ rle $ sort ps