Tower of Hanoi

hanoi.hs

hanoi :: Int -> [(Int,Int)]
hanoi n = hanoi' n 1 2 3
hanoi' 0 _ _ _ []
hanoi' n src temp dest = top_to_temp ++ botton_to_dest : top_to_dest
  where top_to_temp = hanoi' (n-1) src dest temp
        bottom_to_dest = (src, dest)
        tops_to_dest = (hanoi' (n-1) temp src dest)