Problem twelve, and a utility module

012.hs

@@ -1,31 +1,14 @@
-divisors :: Integer -> [Integer]
-divisors n = [ d | d <- [1..n], mod n d == 0 ]
-
-numDivs :: Integer -> Int
-numDivs = length . divisors
+import SimpleMath
 
 tri :: Integer -> Integer
 tri n = n * (n+1) `quot` 2
 
-hm :: Integer -> Int
-hm n = if (even n)
+triDivs :: Integer -> Int
+triDivs n = if (even n)
 			then numDivs (quot n 2) * numDivs (n+1)
 			else numDivs n * numDivs (quot (n+1) 2)
 
-contenders :: Integer -> [Integer]
-contenders n = twosMap [1..n]
-
-twosMap :: [Integer] -> [Integer]
-twosMap [] = []
-twosMap (x:xs) = twos x ++ twosMap xs
-
-twos :: Integer -> [Integer]
-twos n = (2^n - 1) : [2^n]
-
-triDivTriple :: Integer -> (Integer, Integer, Int)
-triDivTriple n = (n, tri n, hm n)
-
-tripleAbove :: Int -> (Integer, Integer, Int) -> Bool
-tripleAbove n (_, _, m) = (m > n)
-
-{-- filter (tripleAbove 500) $ map triDivTriple $ contenders 20 --}
+euler12 :: Int -> (Integer, Integer, Int)
+euler12 n = head $ filter (tripleAbove n) $ map triDivTriple [1..]
+	where triDivTriple m = (m, tri m, triDivs m)
+		  tripleAbove n (_, _, m) = (m > n)

SimpleMath.hs

@@ -0,0 +1,10 @@
+module SimpleMath  
+( divisors  
+, numDivs
+) where 
+
+divisors :: Integer -> [Integer]
+divisors n = [ d | d <- [1..n], mod n d == 0 ]
+
+numDivs :: Integer -> Int
+numDivs = length . divisors