Ethiopian multiplication: Difference between revisions
m
→Haskell :: Fold after unfold: (Tidied)
m (→Haskell :: Fold after unfold: (Tidied)) |
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Line 2,125:
ethMult :: Int -> Int -> Int
ethMult n m =
( trace
. ((showDoubles pairs <> " = ") <>)
. show
)
where
pairs = zip (unfoldr halved n) (iterate doubled m)
Line 2,138 ⟶ 2,141:
(swap $ quotRem h 2)
| otherwise = Nothing
▲ v = foldr addedWhereOdd 0 pairs
addedWhereOdd (d, x) a
| 0 < d = (+) a x
Line 2,163 ⟶ 2,166:
rjust :: Int -> Char -> String -> String
rjust n c s = drop (length s) (replicate n c <> s)
--------------------------- TEST -------------------------
| |||