├── README.md
└── str8ts.pl


/README.md:
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 1 | str8ts solver with constraint programming
 2 | ======
 3 | written in [SWI-Prolog](http://www.swi-prolog.org/) using the [clpfd library](http://www.swi-prolog.org/man/clpfd.html)
 4 | 
 5 | more about str8ts puzzles and their rules at [http://www.str8ts.com/](http://www.str8ts.com/)
 6 | 
 7 | usage
 8 | -----
 9 | 	Puzzle = [[1,2,3,4,5,6,7,_,"b"],
10 | 	          [2,3,4,5,_,7,8,9,"b"],
11 | 	          [3,_,"b",6,7,_,"b","b","b"],
12 | 	          [_,5,6,7,8,"b",1,_,"b"],
13 | 	          [5,6,7,8,9,1,2,3,4],
14 | 	          [_,7,8,_,"b",2,_,4,5],
15 | 	          [7,_,"b",1,2,_,4,"b",_],
16 | 	          [_,9,"b",2,3,4,_,6,7],
17 | 	          ["b",1,_,3,4,"b5",6,_,8]], str8ts(Puzzle).
18 | 
19 | 
20 | known issues
21 | --------
22 | - depending on the puzzle more than ~25 empty cells will result in very long computation times with an exponential increase with each additional empty cell
23 | 


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/str8ts.pl:
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 1 | :- use_module(library(clpfd)).
 2 | 
 3 | str8ts(Puzzle):-
 4 | 				maplist(magic, Puzzle),         
 5 | 				transpose(Puzzle, PuzzleT),     
 6 | 				maplist(magic, PuzzleT),        
 7 | 				printstr8ts(Puzzle).            
 8 | 
 9 | compartment([]).                               
10 | compartment(Compartment) :-
11 | 				length(Compartment,Laenge),
12 | 				minimum(Compartment,Min),
13 | 				maximum(Compartment,Max),
14 | 				Laenge-1 #= Max-Min.      
15 | 
16 | minimum([Min],Min).                            
17 | minimum([X,Y|Tail],Min) :- X #=< Y, minimum([X|Tail],Min).
18 | minimum([X,Y|Tail],Min) :- X #> Y, minimum([Y|Tail],Min).
19 | 
20 | maximum([Max],Max).                            
21 | maximum([X,Y|Tail],Max) :- X #>= Y, maximum([X|Tail],Max).
22 | maximum([X,Y|Tail],Max) :- X #< Y, maximum([Y|Tail],Max).
23 | 
24 | magic([]).                                     
25 | magic(Row):-
26 | 				findcompartment(Row, ListC),
27 | 				findbnumbers(Row, ListB),
28 | 				append(ListC, ListCmerged),
29 | 				ListCmerged ins 1..9,
30 | 				append(ListB, ListCmerged, List),
31 | 				all_different(List),
32 | 				maplist(compartment, ListC).
33 | 
34 | findcompartment([],[]).                        
35 | findcompartment(Row, [Comp|ListC]):-
36 |                 split(Row, Comp, Rest),
37 |                 findcompartment(Rest, ListC), !.
38 | 
39 | 
40 | split([],[],[]).                               
41 | split([X|Tail], [], Rest):-
42 |                 is_list(X),
43 |                 X = [A|_],
44 |                 [A] == "b",
45 |                 Rest = Tail, !.
46 | split([X|Tail], [X|Start], Rest):-
47 |                 split(Tail, Start, Rest).
48 | 
49 | findbnumbers([],[]).                           
50 | findbnumbers([X|Tail], [S|Bs]):-
51 |                 is_list(X),
52 |                 length(X,2),
53 |                 X = [A,B],
54 |                 [A] == "b",
55 |                 number_codes(S, [B]),
56 |                 number(S),
57 |                 findbnumbers(Tail, Bs), !.
58 | findbnumbers([_|Tail], Bs):-  findbnumbers(Tail, Bs).
59 | 
60 | printstr8ts(Puzzle):-                          
61 | 				maplist(printrow, Puzzle).
62 | 
63 | printrow(Row):-
64 |                 printzeichen(Row),
65 |                 writeln('').
66 | 
67 | printzeichen([]).
68 | printzeichen([X|Tail]):-
69 |                 is_list(X),
70 |                 length(X,2),
71 |                 writef("%s", [X]),
72 |                 write(' '),
73 |                 printzeichen(Tail), !.
74 | printzeichen([X|Tail]):-
75 |                 is_list(X),
76 |                 length(X,1),
77 |                 writef(" %s", [X]),
78 |                 write(' '),
79 |                 printzeichen(Tail), !.
80 | printzeichen([X|Tail]):-
81 |                 write(' '),
82 |                 write(X),
83 |                 write(' '),
84 |                 printzeichen(Tail).
85 | 
86 | 


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