--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/hashTest.hs	Sat Sep 21 22:32:01 2013 +0400
@@ -0,0 +1,50 @@
+module Test where
+
+import Control.Monad
+import Data.Word
+import qualified Data.IntSet as IS
+
+data OP = Sum
+        | Mul
+        | Sub
+    deriving Show
+
+
+genOps :: Int -> [[OP]]
+genOps 1 = [[Sum], [Mul], [Sub]]
+genOps n = [a : as | a <- [Sum, Mul, Sub], as <- genOps (n - 1)]
+
+
+genPos :: Int -> Int -> [[Int]]
+genPos m 1 = map (:[]) [-m..m - 1]
+genPos m n = [a : as | a <- [-m..m - 1], as <- genPos m (n - 1)]
+
+
+hash :: [Int] -> [OP] -> [Int] -> Int
+hash poss op s = foldl applyOp s' (zip ss op)
+    where
+        applyOp v (n, Sum) = (v + n) `mod` 256
+        applyOp v (n, Mul) = (v * n) `mod` 256
+        applyOp v (n, Sub) = (v - n) `mod` 256
+        (s' : ss) = map (\p -> if p >= 0 then s !! p else s !! (l + p)) poss
+        l = length s
+
+
+test = do
+    a <- liftM lines getContents
+    let w = minimum $ map length a
+    let opsNum = 4
+    let opsList = genOps (opsNum - 1)
+    let posList = genPos w opsNum
+    let target = length a
+    let wordsList = map (map fromEnum) a
+    let hashedSize = IS.size . IS.fromList
+    print $ length a
+    putStrLn . unlines . map show $ filter (\l -> fst l == length a) $ [(hs, (p, o)) | p <- posList, o <- opsList, let hs = hashedSize . map (hash p o) $ wordsList]
+
+didIunderstand' = do
+    a <- liftM lines getContents
+    print . IS.size . IS.fromList . map (testHash . map fromEnum) $ a
+    where
+        testHash s = let l = length s in
+                         (s !! (l - 2) * s !! 1) + s !! (l - 1) - s !! 0