Update the 'disjoint' function to work on Vectors instead of lists.

diff --git a/src/Misc.hs b/src/Misc.hs
index 16b0ead151ad1b29190028db01aa98ef34d6b797..57dfd433e2ffc4b72cb8daa00f19f94443813404 100644 (file)
--- a/src/Misc.hs
+++ b/src/Misc.hs
@@ -3,7 +3,7 @@
 module Misc
 where
 
-import Data.List (intersect)
+import qualified Data.Vector as V (Vector, elem, empty, filter)
 import Test.Framework (Test, testGroup)
 import Test.Framework.Providers.HUnit (testCase)
 import Test.Framework.Providers.QuickCheck2 (testProperty)
@@ -66,22 +66,27 @@ all_equal xs =
       other_elements = tail xs
 
 
--- | Returns 'True' if the lists xs and ys are disjoint, 'False'
+-- | Returns 'True' if the vectors xs and ys are disjoint, 'False'
 --   otherwise.
 --
 --   Examples:
 --
---   >>> disjoint [1,2,3] [4,5,6]
+--   >>> let xs = Data.Vector.fromList [1,2,3]
+--   >>> let ys = Data.Vector.fromList [4,5,6]
+--   >>> disjoint xs ys
 --   True
 --
---   >>>  disjoint [1,2,3] [3,4,5]
+--   >>> let ys = Data.Vector.fromList [3,4,5]
+--   >>> disjoint xs ys
 --   False
 --
-disjoint :: (Eq a) => [a] -> [a] -> Bool
+disjoint :: (Eq a) => V.Vector a -> V.Vector a -> Bool
 disjoint xs ys =
-    intersect xs ys == []
-
-
+  intersect xs ys == V.empty
+  where
+    intersect :: (Eq a) => V.Vector a -> V.Vector a -> V.Vector a
+    intersect ws zs =
+      V.filter (`V.elem` zs) ws
 
 prop_factorial_greater :: Int -> Property
 prop_factorial_greater n =