2013-11-03 14:12:38 +00:00
|
|
|
%% -*- prolog -*-
|
|
|
|
%%=============================================================================
|
|
|
|
%% Copyright (C) 2011 by Denys Duchier
|
|
|
|
%%
|
|
|
|
%% This program is free software: you can redistribute it and/or modify it
|
|
|
|
%% under the terms of the GNU Lesser General Public License as published by the
|
|
|
|
%% Free Software Foundation, either version 3 of the License, or (at your
|
|
|
|
%% option) any later version.
|
|
|
|
%%
|
|
|
|
%% This program is distributed in the hope that it will be useful, but WITHOUT
|
|
|
|
%% ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
|
|
%% FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
|
|
%% more details.
|
|
|
|
%%
|
|
|
|
%% You should have received a copy of the GNU Lesser General Public License
|
|
|
|
%% along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
%%=============================================================================
|
|
|
|
|
|
|
|
:- use_module(library(gecode)).
|
|
|
|
:- use_module(library(maplist)).
|
|
|
|
|
|
|
|
% use alldiff constraints
|
|
|
|
queens(N, Solution) :-
|
|
|
|
Space := space,
|
|
|
|
length(Queens, N),
|
|
|
|
Queens := intvars(Space,N,1,N),
|
|
|
|
Space += distinct(Queens),
|
|
|
|
foldl(inc, Queens, Inc, 0, _),
|
|
|
|
foldl(dec, Queens, Dec, 0, _),
|
|
|
|
Space += distinct(Inc,Queens),
|
|
|
|
Space += distinct(Dec,Queens),
|
|
|
|
Space += branch(Queens, 'INT_VAR_SIZE_MIN', 'INT_VAL_MIN'),
|
|
|
|
SolSpace := search(Space),
|
|
|
|
Solution := val(SolSpace,Queens).
|
|
|
|
|
|
|
|
inc(_, I0, I0, I) :-
|
|
|
|
I is I0+1.
|
|
|
|
|
|
|
|
dec(_, I0, I0, I) :-
|
|
|
|
I is I0-1.
|
|
|
|
|
|
|
|
%
|
|
|
|
% Using gecode linear constraints for diagonals.
|
|
|
|
%
|
|
|
|
lqueens(N, Solution) :-
|
|
|
|
Space := space,
|
|
|
|
length(Queens, N),
|
|
|
|
Queens := intvars(Space,N,1,N),
|
|
|
|
Space += distinct(Queens),
|
|
|
|
lconstrain( Queens, Space, 0),
|
|
|
|
Space += branch(Queens, 'INT_VAR_SIZE_MIN', 'INT_VAL_MIN'),
|
|
|
|
SolSpace := search(Space),
|
|
|
|
Solution := val(SolSpace,Queens).
|
|
|
|
|
|
|
|
lconstrain([], _, _).
|
|
|
|
lconstrain( [Q|Queens], Space, I0) :-
|
|
|
|
I is I0+1,
|
|
|
|
foldl(constrain(Q, I0, Space), Queens, I, _),
|
|
|
|
lconstrain( Queens, Space, I).
|
|
|
|
|
|
|
|
constrain(Q, I, Space, R, J, J1) :-
|
|
|
|
% Q+I != R+J, Q-I != R-J <=> Q-R != J-I, Q-R != I-J,
|
|
|
|
J1 is J+1,
|
|
|
|
Sum is I-J,
|
|
|
|
Diff is J-I,
|
|
|
|
Space += linear([1,-1], [Q,R], 'IRT_NQ', Diff),
|
2019-03-15 12:38:09 +00:00
|
|
|
Space += linear([1,-1], [Q,R], 'IRT_NQ', Sum).
|