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Discussion on: Daily Challenge #202 - Complete the Pattern II

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avalander profile image
Avalander • • Edited

Haskell

I'm writing this on my phone, so there are probably errors, I'll check it when I have access to a compiler.

pattern :: Int -> String
pattern n
  | n < 1     = " "
  | otherwise = pattern' n
  where
    pattern' n = unlines $ foldl folder [] $ map show [n,(n-1)..1]
    folder :: [String] -> String -> [String]
    folder [] x     = [x]
    folder (p:xs) x = (p ++ x) : p : xs

Edit: fixed issues after running it through a compiler.

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Craig McIlwrath •

I do a lot of these challgnes on my phone. I use rextester.com/l/haskell_online_com... to test my Haskell code a lot.

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Avalander •

Thanks for the tip!