Data commit

Task/Number-reversal-game/Haskell/number-reversal-game.hs

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+import Data.List
+import Control.Arrow
+import Rosetta.Knuthshuffle
+
+numberRevGame = do
+  let goal = [1..9]
+
+      shuffle xs =
+	if xs /= goal then return xs
+		    else shuffle =<< knuthShuffle xs
+
+      prefixFlipAt k = uncurry (++). first reverse. splitAt k
+
+      prompt r ry = do
+	 putStr $ show r ++ ". " ++ concatMap (flip (++) " ". show) ry
+		   ++ " How many to flip? "
+	 answ <- getLine
+	 let n = read answ
+	 if n<10 && 0<n then return n
+	    else do
+	      putStrLn "Error. The number should be between 0 and 10. Try again"
+	      prompt r ry
+
+      playNRG r nrs =
+	if nrs == goal then do
+	  putStrLn $ "The answer is: " ++ concatMap (flip (++) " ". show) nrs
+	  putStrLn $ "It took you " ++ show r ++ " attempts to sort the numbers."
+	  putStrLn ""
+		else do
+		  answ <- prompt r nrs
+		  playNRG (succ r) (prefixFlipAt answ nrs)
+	
+  start <- shuffle goal
+
+  playNRG 1 start