Ethiopian multiplication: Difference between revisions
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This additional generality means that our '''ethMult''' function can now replicate a string n times as readily as it multiplies an integer n times, or raises an integer to the nth power. |
This additional generality means that our '''ethMult''' function can now replicate a string n times as readily as it multiplies an integer n times, or raises an integer to the nth power. |
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<lang haskell>import |
<lang haskell>import Control.Monad (join) |
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import Control.Monad (join) |
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import Data.List (unfoldr) |
import Data.List (unfoldr) |
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import Data.Monoid (getProduct, getSum) |
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import Data.Tuple (swap) |
import Data.Tuple (swap) |
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----------------- ETHIOPIAN MULTIPLICATION --------------- |
----------------- ETHIOPIAN MULTIPLICATION --------------- |
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ethMult |
ethMult :: |
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(Monoid m) => |
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Int -> |
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m -> |
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m |
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ethMult n m = |
ethMult n m = |
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foldr addedWhereOdd mempty $ |
foldr addedWhereOdd mempty $ |
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zip (unfoldr half n) $ iterate (join (<>)) m |
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where |
where |
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half n |
half n |
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main = do |
main = do |
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mapM_ print $ |
mapM_ print $ |
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[ getSum $ ethMult 17 34 -- 34 * 17 |
[ getSum $ ethMult 17 34, -- 34 * 17 |
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getProduct $ ethMult 3 34 -- 34 ^ 3 |
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] |
] |
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-- [3 ^ 17, 4 ^ 17] |
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<> (getProduct <$> ([ethMult 17] <*> [3, 4])) |
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print $ ethMult 17 "34" |
print $ ethMult 17 "34" |
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print $ ethMult 17 [3, 4]</lang> |
print $ ethMult 17 [3, 4]</lang> |
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