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2024-01-22 10:56:12 +00:00
parent d320a956f8
commit dc42625cf1
20 changed files with 293 additions and 10 deletions
--- a/CS1032/lecture-2023-11-23/nqueens.pl
+++ b/CS1032/lecture-2023-11-23/nqueens.pl
@@ -0,0 +1,19 @@
+safe(Q1X-Q1Y, Q2X-Q2Y) :-
+	between(0, 7, Q1Y),
+	between(0, 7, Q2Y),
+	Q1X =\= Q2X,
+	Q1Y =\= Q2Y,
+	abs(Q1X - Q2X) =\= abs(Q1Y - Q2Y).
+safe(_, []).
+safe(QN, [Q | QS]) :- safe(QN, [Q | QS], 1).
+safe(_, [], _).
+safe(QN, [Q | QS], QX) :- safe(0-QN, QX-Q), safe(QN, QS, QX + 1).
+
+add(Qs, QsN) :-
+	QsN = [Q | Qs],
+	safe(Q, Qs).
+
+add(1, Qs, QsN) :- add(Qs, QsN).
+add(N, Qs, QsN) :- add(Qs, QA), add(M, QA, QsN), succ(M, N).
+
+solution(Qs) :- add(8, [], Qs).