Tidying

diff --git a/advent08/Main.hs b/advent08/Main.hs
index 12f0b214f9f904b10930047d045b98bf733b22ad..e822fc278098418b6809c3b9fc9e1978a452de1d 100644 (file)
--- a/advent08/Main.hs
+++ b/advent08/Main.hs
@@ -1,4 +1,4 @@
--- Writeup at https://work.njae.me.uk/2022/12/07/advent-of-code-2022-day-7/
+-- Writeup at https://work.njae.me.uk/2022/12/08/advent-of-code-2022-day-8/
 
 import AoC
 -- import Data.Char
@@ -15,66 +15,65 @@ main =
       text <- readFile dataFileName
       let forest = fmap (fmap readTree) $ lines text
       -- print forest
-      -- print $ findVisibilityOrient forest
-      -- print $ findVisibilityForest forest
-      -- print $ countVisible $ findVisibilityForest forest
+      -- print $ setVisibilityOrient forest
+      -- print $ setVisibilityForest forest
+      -- print $ countVisible $ setVisibilityForest forest
       print $ part1 forest
       print $ part2 forest
       -- print $ part1 sizedTree
       -- print $ part2 sizedTree
 
-part1 :: Forest -> Int
-part1 = countVisible . findVisibilityForest
--- part1, part2 :: STree -> Integer
--- part1 = foldTree (\x xs -> sum (x:xs)) . fmap cancelLarge 
+part1, part2 :: Forest -> Int
+part1 = countVisible . setVisibilityForest
+
+part2 forest = maximum scores
+  where nrows = length forest
+        ncols = length $ head forest
+        scores = [scenicScore forest r c | r <- [0 .. (nrows - 1)], c <- [0 .. (ncols - 1)]]
+
 
 readTree :: Char -> Tree
 readTree h = Tree (read [h]) False
 
-findVisibility :: [Tree] -> [Tree]
-findVisibility row = snd $ foldl' vis (-1, []) row
+isVisible :: Tree -> Bool
+isVisible (Tree _ v) = v
+
+treeHeight :: Tree -> Int
+treeHeight (Tree h _) = h
+
+
+setVisibility :: [Tree] -> [Tree]
+setVisibility row = reverse $ snd $ foldl' vis (-1, []) row
   where vis (highest, tagged) (Tree height visible)
-          | height > highest = (height, tagged ++ [Tree height True])
-          | otherwise = (highest, tagged ++ [Tree height visible])
+          | height > highest = (height, (Tree height True) : tagged)
+          | otherwise = (highest, (Tree height visible) : tagged)
 
-findVisibilityOrient :: Forest -> Forest
-findVisibilityOrient = fmap findVisibility
+setVisibilityOrient :: Forest -> Forest
+setVisibilityOrient = fmap setVisibility
 
-findVisibilityForest :: Forest -> Forest
-findVisibilityForest forest = foldl' f forest [1..4]
-  where f trees _ = findVisibilityOrient (rotate trees)
+setVisibilityForest :: Forest -> Forest
+setVisibilityForest forest = (!!4) $ iterate f forest
+  where f = rotate . setVisibilityOrient
         rotate = (fmap reverse) . transpose 
 
 countVisible :: Forest -> Int
-countVisible forest = length $ filter isVisible $ foldl' (++) [] forest
+countVisible forest = length $ filter isVisible $ concat forest
 
-isVisible :: Tree -> Bool
-isVisible (Tree _ v) = v
 
-treeHeight :: Tree -> Int
-treeHeight (Tree h _) = h
-
-part2 :: Forest -> Int
-part2 forest = maximum scores
-  where nrows = length forest
-        ncols = length $ head forest
-        scores = [scenicScore forest r c | r <- [0 .. (nrows - 1)], c <- [0 .. (ncols - 1)]]
 
 viewDistance :: Int -> [Tree] -> Int
-viewDistance h trees = length $ takeUntil (< h) $ fmap treeHeight trees
+viewDistance h trees = length $ takeWhile1 (< h) $ fmap treeHeight trees
 
-takeUntil :: (a -> Bool) -> [a] -> [a]
-takeUntil f [] = []
-takeUntil f (x:xs) 
-  | f x == True = x : (takeUntil f xs)
+takeWhile1 :: (a -> Bool) -> [a] -> [a]
+takeWhile1 _ [] = []
+takeWhile1 f (x:xs) 
+  | f x == True = x : (takeWhile1 f xs)
   | otherwise = [x]
 
 tracks :: Forest -> Int -> Int -> [[Tree]]
 tracks forest row col = [reverse l, drop 1 r, reverse u, drop 1 d]
   where (l, r) = splitAt col (forest !! row)
-        -- r = drop 1 r'
         (u, d) = splitAt row ((transpose forest) !! col)
-        -- d = drop 1 d'
 
 scenicScore :: Forest -> Int -> Int -> Int
 scenicScore forest row col = foldl' (*) 1 $ fmap (viewDistance h) directions