Subset.hs

-- subset generator
--  ./Test
-- 3
-- [[1,2,3],[2,3],[1,3],[3],[1,2],[2],[1],[]]
-- ./Test
-- 4
-- [[1,2,3,4],[2,3,4],[1,3,4],[3,4],[1,2,4],[2,4],[1,4],[4],[1,2,3],[2,3],[1,3],[3],[1,2],[2],[1],[]]
module Main where

subMain :: Int -> [Int] -> [[Int]]
subMain 0 elements = [elements]
subMain maxNum elements = (subMain (maxNum-1) (maxNum:elements)) ++ (subMain (maxNum-1) elements)

main :: IO ()
main =
    do line <- getLine
       let maxNum = read line :: Int
       let subSets = subMain maxNum []
       print subSets