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lakshayg/knights_and_knaves.prolog

Created March 5, 2024 22:36
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A prolog program to solve the knight and knaves logic puzzles
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knights_and_knaves.prolog
person(knight).
person(knave).
persons(List) :- maplist(person, List).
claim(knight, Stmt) :- Stmt.
claim(knave, Stmt) :- \+Stmt.
% A puzzle taken from https://dmackinnon1.github.io/knaves/
% You have met a group of 6 islanders. Their names are Justin, Samuel, Ira, Frank, Beatrix, and Pamela.
%
% Samuel says: Ira is a knight.
% Samuel says: Justin lies.
% Beatrix says: Frank never lies.
% Beatrix says: Pamela tells the truth.
% Ira says: Frank is a knight or I am a knave.
puzzle(J, S, I, F, B, P) :-
persons([J, S, I, F, B, P]),
claim(S, I = knight),
claim(S, J = knave),
claim(B, F = knight),
claim(B, P = knight),
claim(I, (F = knight; I = knave)).
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