Multiplication tables: Difference between revisions

Or, more roughly and directly:

<lang haskell>import Data.List (groupBy)

import Data.Function (on)

import Control.Monad (join)

main :: IO ()

main =

mapM_ print $

fmap (uncurry (*)) <$>

groupBy

(on (==) fst)

(filter (uncurry (>=)) $ join ((<*>) . fmap (,)) [1 .. 12])</lang>

{{Out}}

<pre>[1]

[2,4]

[3,6,9]

[4,8,12,16]

[5,10,15,20,25]

[6,12,18,24,30,36]

[7,14,21,28,35,42,49]

[8,16,24,32,40,48,56,64]

[9,18,27,36,45,54,63,72,81]

[10,20,30,40,50,60,70,80,90,100]

[11,22,33,44,55,66,77,88,99,110,121]

[12,24,36,48,60,72,84,96,108,120,132,144]</pre>