+20 +21 +22 +23 +24 +25

1 files changed, 21 insertions, 0 deletions

diff --git a/h23.hs b/h23.hs
new file mode 100644
index 0000000..f85a87a
--- /dev/null
+++ b/h23.hs
@@ -0,0 +1,21 @@
+import System.Random
+import Data.List
+
+rnd_select :: [a] -> Int -> IO [a]
+rnd_select _ 0 = return []
+rnd_select (x:xs) n =
+    do 
+        r <- randomRIO (0, (length xs))
+        if r < n
+            then do
+                rest <- rnd_select xs (n-1)
+                return (x : rest)
+            else rnd_select xs n
+
+rnd_select' xs n = do
+    gen <- getStdGen
+    return $ take n [ xs !! x | x <- randomRs (0, (length xs) - 1) gen]
+
+rnd_select'' :: Int -> [a] -> [a]
+rnd_select'' n x = map (x!!) is
+    where is = take n . nub $ randomRs (0, length x - 1) (mkStdGen 100)