port of PYSWIP package.

packages/pyswip/examples/sudoku/sudoku.pl

@@ -0,0 +1,31 @@
+
+% Prolog Sudoku Solver (C) 2007 Markus Triska (triska@gmx.at)
+% Public domain code.
+
+:- use_module(library(clpfd)).
+
+% Pss is a list of lists representing the game board.
+
+sudoku(Pss) :-
+    flatten(Pss, Ps),
+    allin(Ps, 1..9),
+    maplist(all_different, Pss),
+    Pss = [R1,R2,R3,R4,R5,R6,R7,R8,R9],
+    columns(R1, R2, R3, R4, R5, R6, R7, R8, R9),
+    blocks(R1, R2, R3), blocks(R4, R5, R6), blocks(R7, R8, R9),
+    label(Ps).
+
+columns([], [], [], [], [], [], [], [], []).
+columns([A|As],[B|Bs],[C|Cs],[D|Ds],[E|Es],[F|Fs],[G|Gs],[H|Hs],[I|Is]) :-
+    all_different([A,B,C,D,E,F,G,H,I]),
+    columns(As, Bs, Cs, Ds, Es, Fs, Gs, Hs, Is).
+
+blocks([], [], []).
+blocks([X1,X2,X3|R1], [X4,X5,X6|R2], [X7,X8,X9|R3]) :-
+    all_different([X1,X2,X3,X4,X5,X6,X7,X8,X9]),
+    blocks(R1, R2, R3).
+
+allin([],_).
+allin([Pos|Board],D) :-
+	Pos in D,
+	allin(Board,D).