From 378f6303e8860b7bbca7dea787d584a6728cebf1 Mon Sep 17 00:00:00 2001
From: Joe Zhao <ztuowen@gmail.com>
Date: Thu, 19 Mar 2015 16:49:40 +0800
Subject: +28

---
 h28n.hs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 h28n.hs

(limited to 'h28n.hs')

diff --git a/h28n.hs b/h28n.hs
new file mode 100644
index 0000000..bf584c7
--- /dev/null
+++ b/h28n.hs
@@ -0,0 +1,14 @@
+import Control.Arrow ((>>>), (&&&), second)
+import GHC.Exts (sortWith)
+
+lfsort :: [[a]] -> [[a]]
+lfsort = zip [1..] >>> map (second (length &&& id)) >>> sortWith (snd>>>fst)
+            >>> cntDupLength undefined [] >>> sortWith (snd>>>fst) 
+            >>> sortWith fst >>> map (\(_,(_,(_,a))) -> a)
+    where 
+        cntDupLength :: Int -> [(Int,(Int,a))] -> [(Int,(Int,a))] -> [(Int,(Int,(Int,a)))]
+        cntDupLength _ lls [] = map ((,) (length lls)) $ reverse lls
+        cntDupLength _ [] (x@(_,(l,_)):xs) = cntDupLength l [x] xs
+        cntDupLength l lls ys@(x@(_,(l1,_)):xs)
+            | l == l1   = cntDupLength l (x:lls) xs
+            | otherwise = (map ((,) (length lls)) $ reverse lls) ++ cntDupLength undefined [] ys
-- 
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