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 $ length a

    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

                         ) `mod` 256