[Haskell-cafe] I need a hint in list processing

Hi all If I have a number of list example list1 = [2,3] list2 = [1,2] list3 = [2,3,4] list4 = [1,2,3] I want to create a list from the list above with n elements, non-repeating and each elements index represents 1 of the elements from the corresponding list so for the above input I would get. a = [3,2,4,1] ofcourse there may be several set that will satisfy the problem, so a list of list that satisfies would be good. How do I do this in haskell? or is there a code snippet that seems to work similarly? thanks fernan -- http://www.fernski.com