Just another update

Task/Spiral-matrix/Haskell/spiral-matrix-1.hs

@@ -1,12 +1,9 @@
-module Spiral where
-
 import Data.List
 import Control.Monad
-import Control.Monad.Instances
-
 grade xs = map snd. sort $ zip xs [0..]
 values n = cycle [1,n,-1,-n]
 counts n = (n:).concatMap (ap (:) return)  $ [n-1,n-2..1]
 reshape n = unfoldr (\xs -> if null xs then Nothing else Just (splitAt n xs))
-
 spiral n = reshape n . grade. scanl1 (+). concat $ zipWith replicate (counts n) (values n)
+displayRow = putStrLn . intercalate " " . map show
+main = mapM displayRow $ spiral 5

Task/Spiral-matrix/Haskell/spiral-matrix-2.hs

@@ -0,0 +1,9 @@
+import Data.List
+import Control.Applicative
+counts = tail . reverse . concat . map (replicate 2) . enumFromTo 1
+values = cycle . ((++) <$> map id <*> map negate) . (1 :) . (: [])
+grade = map snd . sort . flip zip [0..]
+copies = grade . scanl1 (+) . concat . map (uncurry replicate) . (zip <$> counts <*> values)
+parts = (<*>) take $ (.) <$> (map . take) <*> (iterate . drop) <*> copies
+disp = (>> return ()) . mapM (putStrLn . intercalate " " . map show) . parts
+main = disp 5

Task/Spiral-matrix/Haskell/spiral-matrix-3.hs

@@ -0,0 +1,10 @@
+import Data.List (transpose)
+import Text.Printf (printf)
+
+-- spiral is the first row plus a smaller spiral rotated 90 deg
+spiral 0 _ _ = [[]]
+spiral h w s = [[s .. s+w-1]] ++ rot90 (spiral w (h-1) (s+w))
+	where rot90 = (map reverse).transpose
+
+-- this is sort of hideous, someone may want to fix it
+main = mapM_ (\row->mapM_ ((printf "%4d").toInteger) row >> putStrLn "") (spiral 10 9 1)