QT for some reason messes with XCompose causing broken input (Qt 5 only - Qt 4 did not break anything). In Qt 5.2 and 5.3 this was causing an invalid conversion in chat messages containing these resulting in the bad bytes being stripped. In Qt 5.9 it is still broken, but you at least get a string with something in it. This checks for non-zero converted strings for room creation and chat lines.
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