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Queens.java

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/*
 *  Main authors:
 *     Mikael Lagerkvist <lagerkvist@gecode.org>
 *     Guido Tack <tack@gecode.org>
 *
 *  Copyright:
 *     Mikael Lagerkvist, 2006
 *     Guido Tack, 2006
 *
 *  Last modified:
 *     $Date: 2006-09-26 16:26:14 +0200 (Tue, 26 Sep 2006) $ by $Author: zayenz $
 *     $Revision: 3704 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  See the file "LICENSE" for information on usage and
 *  redistribution of this file, and for a
 *     DISCLAIMER OF ALL WARRANTIES.
 *
 */

package examples;

import static org.gecode.Gecode.*;
import static org.gecode.GecodeEnumConstants.*;

import org.gecode.*;
import org.gecode.explorer.Explorer;

public class Queens extends Space {
    private int n;
    private VarArray<IntVar> q;

    public Queens(Options opt) {
        super();
        n = opt.size;
        q = new VarArray<IntVar>(this, n, IntVar.class, 0, n-1);
        
        int c[] = new int[n];

        for (int i=0; i<n; i++)
            c[i] = i;
        distinct(this, c, q, opt.icl);

        for (int i=0; i<n; i++)
            c[i] = -i;
        distinct(this, c, q, opt.icl);

        distinct(this, q, opt.icl);

        branch(this, q, BVAR_SIZE_MIN, BVAL_MIN);
    }

    public Queens(Boolean share, Queens queens) {
        super(share, queens);
        n = queens.n;
        q = new VarArray<IntVar>(this, share, queens.q);
    }

    public String toString() {
        String res = "";
        
        for (int i = 0; i < n; ++i) {
            char[] l = new char[n];
            for (int j=0;j<n;++j) l[j] = '\u00B7';

            if (q.get(i).assigned()) {
                l[q.get(i).val()] = 'Q';
            } else {
                for (Range r : new IntVarRanges(q.get(i)))
                  for (int j : r)
                    l[j] = 'q';
            }
            res += new String(l);
            res += "\n";
        }
        return res;
    }

    public static void main(String[] args) {
        Options opt = new Options();
        opt.size = 6;
        opt.gui = true;
        opt.parse(args);
        opt.name = "" + opt.size + "-Queens";

        Queens queens = new Queens(opt);
        opt.doSearch(queens);
    }
}