24_b_1, 24_b_2: Add solution

1 files changed, 56 insertions, 0 deletions

diff --git a/ch24/Sorting.hs b/ch24/Sorting.hs
new file mode 100644
index 0000000..6fb9870
--- /dev/null
+++ b/ch24/Sorting.hs
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+{-- snippet parSort --}

+module Sorting where

+

+import Control.Parallel (par, pseq)

+

+parSort :: (Ord a) => [a] -> [a]

+parSort (x:xs)    = force greater `par` (force lesser `pseq`

+                                         (lesser ++ x:greater))

+    where lesser  = parSort [y | y <- xs, y <  x]

+          greater = parSort [y | y <- xs, y >= x]

+parSort _         = []

+{-- /snippet parSort --}

+

+{-- snippet sillySort --}

+sillySort (x:xs) = greater `par` (lesser `pseq`

+                                  (lesser ++ x:greater))

+    where lesser   = sillySort [y | y <- xs, y <  x]

+          greater  = sillySort [y | y <- xs, y >= x]

+sillySort _        = []

+{-- /snippet sillySort --}

+

+{-- snippet sort --}

+sort :: (Ord a) => [a] -> [a]

+sort (x:xs) = lesser ++ x:greater

+    where lesser  = sort [y | y <- xs, y <  x]

+          greater = sort [y | y <- xs, y >= x]

+sort _ = []

+{-- /snippet sort --}

+

+{-- snippet seqSort --}

+seqSort :: (Ord a) => [a] -> [a]

+seqSort (x:xs) = lesser `pseq` (greater `pseq`

+                                (lesser ++ x:greater))

+    where lesser  = seqSort [y | y <- xs, y <  x]

+          greater = seqSort [y | y <- xs, y >= x]

+seqSort _ = []

+{-- /snippet seqSort --}

+

+{-- snippet force --}

+force :: [a] -> ()

+force xs = go xs `pseq` ()

+    where go (_:xs) = go xs

+          go [] = 1

+{-- /snippet force --}

+

+{-- snippet parSort2 --}

+parSort2 :: (Ord a) => Int -> [a] -> [a]

+parSort2 d list@(x:xs)

+  | d <= 0     = sort list

+  | otherwise = force greater `par` (force lesser `pseq`

+                                     (lesser ++ x:greater))

+      where lesser      = parSort2 d' [y | y <- xs, y <  x]

+            greater     = parSort2 d' [y | y <- xs, y >= x]

+            d' = d - 1

+parSort2 _ _              = []

+{-- /snippet parSort2 --}