fork download

import Data.Array  (Array, (!), (//), bounds, listArray)
 
-- matrixes :: Int -> [[(Int, Int)]]
matrixes n = go 1 . listArray (1, 9) . repeat $ 9
  where
    go :: Int -> Array Int Int -> [[Int]]
    go i rs = let maxIndex = snd (bounds rs) 
                  r        = rs ! i
              in  if      i > maxIndex then []
                  else if r == 0       then go (i + 1) rs
                  else                      map (i :) (go 1 (rs // [(i, (rs ! i) - 1)])) ++ go (i + 1) rs
 
 

[1 of 1] Compiling Main             ( prog.hs, prog.o )

prog.hs:1:1: error:
    The IO action ‘main’ is not defined in module ‘Main’
  |
1 | import Data.Array  (Array, (!), (//), bounds, listArray)
  | ^

Standard output is empty