org.chocosolver.samples.nqueen.NQueenBinary Maven / Gradle / Ivy

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/**
 * Copyright (c) 2015, Ecole des Mines de Nantes
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the .
 * 4. Neither the name of the  nor the
 *    names of its contributors may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY  ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL  BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.chocosolver.samples.nqueen;

import org.chocosolver.solver.constraints.Constraint;
import org.chocosolver.solver.constraints.IntConstraintFactory;
import org.chocosolver.solver.search.strategy.IntStrategyFactory;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.VariableFactory;

import java.util.HashSet;

/**
 * 

 *
 * @author Charles Prud'homme
 * @since 31/03/11
 */
public class NQueenBinary extends AbstractNQueen {

    HashSet set;

    @Override
    public void buildModel() {
        set = new HashSet<>();
        vars = new IntVar[n];
        for (int i = 0; i < vars.length; i++) {
            vars[i] = VariableFactory.enumerated("Q_" + i, 1, n, solver);
        }


        for (int i = 0; i < n - 1; i++) {
            for (int j = i + 1; j < n; j++) {
                int k = j - i;
                Constraint neq = IntConstraintFactory.arithm(vars[i], "!=", vars[j]);
                solver.post(neq);
                set.add(neq);
                solver.post(IntConstraintFactory.arithm(vars[i], "!=", vars[j], "+", -k));
                solver.post(IntConstraintFactory.arithm(vars[i], "!=", vars[j], "+", k));
            }
        }
    }

    @Override
    public void configureSearch() {
        solver.set(IntStrategyFactory.minDom_LB(vars));
//        SearchMonitorFactory.log(solver, true, false);
    }

    public static void main(String[] args) {
        new NQueenBinary().execute(args);
    }
}