Added samples for Haskell

samples/Haskell/Sudoku.hs

@@ -0,0 +1,46 @@
+module Sudoku
+(
+  Sudoku,
+  solve,
+  isSolved,
+  pPrint
+) where
+
+import Data.Maybe
+import Data.List
+import Data.List.Split
+
+type Sudoku = [Int]
+
+solve :: Sudoku -> Maybe Sudoku
+solve sudoku
+  | isSolved sudoku = Just sudoku
+  | otherwise = do
+    index <- elemIndex 0 sudoku
+    let sudokus = [nextTest sudoku index i | i <- [1..9],
+                                  checkRow (nextTest sudoku index i) index,
+                                  checkColumn (nextTest sudoku index i) index,
+                                  checkBox (nextTest sudoku index i) index]
+    listToMaybe $ mapMaybe solve sudokus
+  where nextTest sudoku index i = take index sudoku ++ [i] ++ drop (index+1) sudoku
+        checkRow sudoku index = (length $ getRow sudoku index) == (length $ nub $ getRow sudoku index)
+        checkColumn sudoku index = (length $ getColumn sudoku index) == (length $ nub $ getColumn sudoku index)
+        checkBox sudoku index = (length $ getBox sudoku index) == (length $ nub $ getBox sudoku index)
+        getRow sudoku index = filter (/=0) $ (chunksOf 9 sudoku) !! (quot index 9)
+        getColumn sudoku index = filter (/=0) $ (transpose $ chunksOf 9 sudoku) !! (mod index 9)
+        getBox sudoku index = filter (/=0) $ (map concat $ concatMap transpose $ chunksOf 3 $ map (chunksOf 3) $ chunksOf 9 sudoku)
+                                                                                !! (3 * (quot index 27) + (quot (mod index 9) 3))
+
+isSolved :: Sudoku -> Bool
+isSolved sudoku
+  | product sudoku == 0 = False
+  | map (length . nub) sudokuRows /= map length sudokuRows = False
+  | map (length . nub) sudokuColumns /= map length sudokuColumns = False
+  | map (length . nub) sudokuBoxes /= map length sudokuBoxes = False
+  | otherwise = True
+  where sudokuRows = chunksOf 9 sudoku
+        sudokuColumns = transpose sudokuRows
+        sudokuBoxes = map concat $ concatMap transpose $ chunksOf 3 $ map (chunksOf 3) $ chunksOf 9 sudoku
+
+pPrint :: Sudoku -> String
+pPrint sudoku = intercalate "\n" $ map (intercalate " " . map show) $ chunksOf 9 sudoku