IntegerPartitions

IntegerPartitions.dcl

definition module IntegerPartitions

integerPartitions :: Int Int -> [[Int]]

IntegerPartitions.icl

implementation module IntegerPartitions
import StdEnv

table :: [[[[Int]]]]
table =: [f m \\ m <- [1..]] where
    f m = [g m n \\ n <- [1..m]] where
        g m n
            | m < n     = [[]]
            | m == n    = [repeatn m 1]
            | n == 1    = [[m]]
            | otherwise = map (add1 n) (flatten [integerPartitions (m-n) x \\ x <- [1..min (m-n) n]])
        where
            add1 len xs = take len [x+1 \\ x <- xs ++ (repeat 0)]

integerPartitions :: Int Int -> [[Int]]
integerPartitions m n = table !! (m-1) !! (n-1)