org.xcsp.modeler.problems.Sudoku Maven / Gradle / Ivy

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Java Tools for parsing XCSP3 instances, compiling JvCSP3 models, and checking solutions. For more information about XCSP3, follow www.xcsp.org

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/**
 * AbsCon - Copyright (c) 2017, CRIL-CNRS - [email protected]
 * 
 * All rights reserved.
 * 
 * This program and the accompanying materials are made available under the terms of the CONTRAT DE LICENCE DE LOGICIEL LIBRE CeCILL which accompanies this
 * distribution, and is available at http://www.cecill.info
 */
package org.xcsp.modeler.problems;

import org.xcsp.common.IVar.Var;
import org.xcsp.modeler.api.ProblemAPI;

public class Sudoku implements ProblemAPI {

	int n; // order of the grid (typically, 9)
	int[][] clues; // if not 0, clues[i][j] is a value imposed at row i and col j

	@Override
	public void model() {
		int base = (int) Math.sqrt(n);

		Var[][] x = array("x", size(n, n), dom(rangeClosed(1, n)), "x[i][j] is the value in cell at row i and col j.");

		allDifferentMatrix(x);
		forall(range(0, n, base).range(0, n, base), (i, j) -> allDifferent(select(x, range(i, i + base).range(j, j + base)))).tag(BLOCKS);
		instantiation(x, clues, onlyOn((i, j) -> clues[i][j] != 0)).tag(CLUES);
	}
}