From ce3466f7466e21bc3d8e1d2fb2c1992cdb0c80e0 Mon Sep 17 00:00:00 2001
From: Jens Kadenbach <jens.kadenbach@smartsteuer.de>
Date: Thu, 8 Dec 2022 13:58:34 +0100
Subject: [PATCH] Day 8 - cleanup

---
 src/Day8.hs      | 25 +++++++++++--------------
 test/Day8Spec.hs |  3 +--
 2 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/src/Day8.hs b/src/Day8.hs
index b116228..a1a27a5 100644
--- a/src/Day8.hs
+++ b/src/Day8.hs
@@ -35,9 +35,9 @@ checkAgainstNeighbours f forest  = M.matrix (M.nrows forest) (M.ncols forest) ch
       let row = M.getRow x forest
           col = M.getCol y forest
           -- left and top are reversed to order the as seen from (x,y)
-          left   = V.reverse $ V.take (y - 1) row 
+          left   = V.reverse $ V.take (y - 1) row
           right  = V.drop y row
-          top    = V.reverse $ V.take (x - 1) col 
+          top    = V.reverse $ V.take (x - 1) col
           bottom = V.drop x col
           v = forest ! (x,y)
       in f v [left, right, top, bottom]
@@ -45,10 +45,10 @@ checkAgainstNeighbours f forest  = M.matrix (M.nrows forest) (M.ncols forest) ch
 checkVisibility :: Forest -> Visibillity
 checkVisibility = checkAgainstNeighbours isVisible
   where
-    isVisible v = any (all (< v))
+    isVisible treeHeight = any (all (< treeHeight))
 
 countVisible :: Visibillity -> Int
-countVisible vis = getSum $ foldMap (Sum . isTrue) vis
+countVisible = foldMap (Sum . isTrue) >>> getSum
   where
     isTrue True = 1
     isTrue False = 0
@@ -56,29 +56,26 @@ countVisible vis = getSum $ foldMap (Sum . isTrue) vis
 checkScenicScores :: Forest -> M.Matrix Int
 checkScenicScores = checkAgainstNeighbours allDistances
   where
-    allDistances tree neighbors = getProduct $ foldMap (Product . viewingDistance tree) neighbors
+    allDistances treeHeight neighbors = foldMap (viewingDistance treeHeight >>> Product) >>> getProduct $ neighbors
 
 viewingDistance :: Int -> V.Vector Int -> Int
 viewingDistance treeHeight neighbors
-  | V.length neighbors == 0 = 0
-  | V.head neighbors >= treeHeight = 1
-  | V.head neighbors < treeHeight = 1 + viewingDistance treeHeight (V.tail neighbors)
+  | V.length neighbors == 0         = 0
+  | V.head neighbors >= treeHeight  = 1
+  | V.head neighbors <  treeHeight  = 1 + viewingDistance treeHeight (V.tail neighbors)
   | otherwise = 0
 
 findMaxScenicScore :: Forest -> Int
-findMaxScenicScore forest = maximum $ M.toList scores
-  where
-    scores = checkScenicScores forest
+findMaxScenicScore = checkScenicScores >>> M.toList >>> maximum
 
 day8 :: IO ()
 day8 = do
    input <- readFile "ressources/day08-input"
    putStrLn "Day8"
    let forest = parseForest input
-   let visibleTrees = checkVisibility >>>
-                      countVisible $ forest
+   let visibleTrees = checkVisibility >>> countVisible $ forest
    putStrLn ("Number of visible trees is " ++ show visibleTrees)
    let highestScenicScore = findMaxScenicScore forest
    putStrLn ("Highest scenic score is " ++ show highestScenicScore)
-   
+
 
diff --git a/test/Day8Spec.hs b/test/Day8Spec.hs
index ceaf9cf..da27cd8 100644
--- a/test/Day8Spec.hs
+++ b/test/Day8Spec.hs
@@ -23,8 +23,7 @@ testVisibility = M.fromList 5 5
    x,x,x,o,x,
    x,x,o,x,x,
    x,o,x,o,x,
-   x,x,x,x,x
-  ]
+   x,x,x,x,x]
   where
     x = True
     o = False