Find all combinations of a given set of numbers

Question

say I have a set of numbers \'0\', \'1\', \'2\', ..., \'9\'. I want to find all numbers that contain exactly one of each of the numbers in my set.

The problem is: Be

Answer 1

import Data.List (inits, tails)

place :: a -> [a] -> [[a]]
place element list = zipWith (\front back -> front ++ element:back)
                             (inits list)
                             (tails list)

perm :: [a] -> [[a]]
perm = foldr (\element rest -> concat (map (place element) rest)) [[]]

test = perm [1, 3, 14]