Bruteforce

import Data.List (elemIndex)

combinationId :: Eq a => [a] -> [a] -> Maybe Integer
combinationId alphabet string =
   let a = toInteger $ length alphabet
       n = toInteger $ length string
       result = baseCombinationDistance alphabet string
   in
       case result of
           Just distance -> Just $ distance + (a^n - 1) `div` (a - 1)
           Nothing -> result
           
baseCombinationDistance alphabet [] = Just 0            
baseCombinationDistance alphabet (x : xs) =
   let maybePos = x `elemIndex` alphabet        
   in
       case maybePos of
           Just pos ->
               let result = baseCombinationDistance alphabet xs
                   a = toInteger $ length alphabet
                   n = toInteger $ length xs
               in
                   case result of
                       Just steps -> Just $ (toInteger pos) * a ^ n + steps
                       Nothing -> Nothing
           Nothing -> Nothing

main = do
       putStr "Insert how many password are generated each second: "
       pwdPerSecIn <- getLine        
       putStr "Insert the password to find: "
       password <- getLine

       let alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()-_+=~`[]{}|\\:;\"\\'<>,.?/"
       let combination = combinationId alphabet password
       let pwdPerSec = read pwdPerSecIn :: Integer        

       let msg = case combination of
               Just id ->  "Password found after " ++ show id ++ " steps in " ++ (show $ id `div` pwdPerSec) ++ " seconds."
               Nothing -> "Password not found."  

       putStrLn msg