1 member(X,[X|_]).

2 member(X,[_|List]) :- member(X,List).

3

4 adjacent(X,Y,Map) :- member([X,Y],Map) ; member([Y,X],Map).

5

6

7 find_regions([],R,R).

8 find_regions([[X,Y]|S], R,A) :-

9 (member(X,R) ->

10 (member(Y,R) -> find_regions(S,R,A) ; find_regions(S,[Y|R],A)) ;

11 (member(Y,R) -> find_regions(S,[X|R],A) ; find_regions(S,[X,Y|R],A) )).

12

13

14 color(Map,Colors,Coloring) :-

15 find_regions(Map,[],Regions),

16 color_all(Regions,Colors,Coloring),

17 not(conflict(Map,Coloring)).

18 color_all([R|Rs],Colors,[[R,C]|A]) :-

19 member(C,Colors),

20 color_all(Rs,Colors,A).

21 color_all([],_,[]).

22

23 conflict(Map,Coloring) :- member([R1,C],Coloring),

24 member([R2,C],Coloring),

25 adjacent(R1,R2,Map).

26

27 map1([[1,2],[1,3],[1,4],[1,5],[2,3],[2,4],[3,4],[4,5]]).

28 map2([[1,2],[2,3],[1,3]]).

29 map3([[1,2]]).

30

31

32