Haskell Quiz/PP Pascal/Solution Jethr0
< Haskell Quiz | PP Pascal
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Example:
> pp_pascal 10
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
1 6 15 20 15 6 1
1 7 21 35 35 21 7 1
1 8 28 56 70 56 28 8 1
1 9 36 84 126 126 84 36 9 1
Solution:
-- also using the pascal triangle function from [[Blow your Mind]]
pp_pascal n = unlines . map (center . showp) $ pascal
where pascal = take n $ iterate (\row -> zipWith (+) ([0] ++ row) (row ++ [0])) [1]
showp = concat . intersperse " " . map show
len = length . showp $ last pascal
center s = replicate ((len - (length s)) `div` 2) ' ' ++ s