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Acorn Arcade forums: Programming: PROLOG Lists pleas help
 
  PROLOG Lists pleas help
  gilly_uk (20:31 30/11/2002)
 
andrew Message #25727, posted by gilly_uk at 20:31, 30/11/2002
Member
Posts: 1 		Im revising for an exam next week and i cant get my head round this exercise in the notes i have. Its asks to use the method call
move(PermutationList,NewPermutationList).

Where given a permutation list as input, will produce as output a list identical to the first but in which two elements have been swapped. Through backtracking the procedure should produce all possible swaps.

e.g
move([2,1],SL).
SL = [1,2]

move([1,2,3],SL).
SL = [2,1,3]
SL = [3,2,1]
SL = [1,3,2]

I have written some code which works for [2,1] but thats it.

move([],[]).

move([H,T|Rest],[T,H|Rest]):-
move(Rest,Rest).

please help me
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Acorn Arcade forums: Programming: PROLOG Lists pleas help