Haskell program to consistently print lines

consistent_printer.hs

import System.Environment
import Data.List.Split
import Data.List
import Data.List.Utils (replace)
import Data.String.Utils (strip)

getStringList :: String -> [String]
getStringList str = splitOn " " str

-- costAtJ is the cost incurred by placing a newline
-- after j.
costAtJ :: [String] -> Int -> Int -> Int -> Int
costAtJ list max_line_length i j
  | lineLength > max_line_length = (maxBound :: Int)
  | otherwise = previous_cost + extra_space ^ 2
  where lineLength = length (intercalate " " (drop j (take i list)))
        previous_cost :: Int
        previous_cost
          | j == 0 = 0
          | otherwise = costOf j list max_line_length
        extra_space = max_line_length - lineLength
        
-- costOf i refers to the minimum cost if linebreak
-- is placed after the ith word.
costOf :: Int -> [String] -> Int -> Int
costOf i list max_line_length
  | i == 0 = 0
  | otherwise = minimum costAtEachJ
  where costAtEachJ = map (costAtJ list max_line_length i) [0..i-1]
  
minExtraSpaceCost :: [String] -> Int -> Int
minExtraSpaceCost list max_line_length =
  costOf (length list) list max_line_length
  
main = do
    [lineLengthRaw, fileName] <- getArgs
    contents <- readFile fileName
    let maxLineLength = read lineLengthRaw :: Int
    let strippedString = replace "\n" " " (strip contents)
    putStr (show (minExtraSpaceCost (getStringList strippedString) maxLineLength))