Haskell Quiz/PP Pascal/Solution Ltriant
< Haskell Quiz | PP Pascal
Jump to navigation
Jump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
Works...kind of; adds a space or two (or three) to the end of each line.
module Main where
import System.Environment ( getArgs )
fac n = product [1..n]
nck n k = (fac n) `div` ((fac $ n - k) * (fac k))
space_len n = mylength $ show $ (n-1) `nck` ((n-1) `div` 2)
mylength = toInteger . length
indent n t =
(concat $ replicate (fromInteger $ (n-p) * space_len n) " "):t
where p = mylength t
space_out n t =
map (\x -> show x ++ (concat $ replicate (num_spaces x) " ")) t
where num_spaces x = fromInteger $ (2 * space_len n) - (mylength $ show x)
pp_pascal n =
map (concat . indent n . space_out n) $ f 0 n
where f acc n | acc == n = []
| otherwise = (map (nck acc) [0..acc]):(f (acc+1) n)
main =
do args <- getArgs
case args of
[v] -> mapM_ putStrLn $ pp_pascal (read v :: Integer)
_ -> error "No argument specified."