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Open-source constraint solver.
/*
* This file is part of choco-solver, http://choco-solver.org/
*
* Copyright (c) 2023, IMT Atlantique. All rights reserved.
*
* Licensed under the BSD 4-clause license.
*
* See LICENSE file in the project root for full license information.
*/
/**
* Created by IntelliJ IDEA.
* User: Jean-Guillaume Fages
* Date: 14/01/13
* Time: 16:36
*/
package org.chocosolver.solver.constraints.set;
import org.chocosolver.solver.constraints.Propagator;
import org.chocosolver.solver.constraints.PropagatorPriority;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.variables.SetVar;
import org.chocosolver.util.ESat;
import org.chocosolver.util.objects.setDataStructures.ISetIterator;
/**
* Ensures that all sets are different
*
* @author Jean-Guillaume Fages
*/
public class PropAllDiff extends Propagator {
//***********************************************************************************
// VARIABLES
//***********************************************************************************
private final int n;
//***********************************************************************************
// CONSTRUCTORS
//***********************************************************************************
/**
* Ensures that all sets are different
*
* @param sets array of set variables
*/
public PropAllDiff(SetVar[] sets) {
super(sets, PropagatorPriority.LINEAR, true);
n = sets.length;
}
//***********************************************************************************
// METHODS
//***********************************************************************************
@Override
public void propagate(int evtmask) throws ContradictionException {
for (int i = 0; i < n; i++) {
if (vars[i].isInstantiated()) {
propagate(i, 0);
}
}
}
@Override
public void propagate(int idx, int mask) throws ContradictionException {
if (vars[idx].isInstantiated()) {
int s = vars[idx].getUB().size();
for (int i = 0; i < n; i++) {
if (i != idx) {
int sei = vars[i].getUB().size();
int ski = vars[i].getLB().size();
if (ski >= s - 1 && sei <= s + 1) {
int nbSameInKer = 0;
int diff = -1;
ISetIterator iter = vars[idx].getLB().iterator();
while (iter.hasNext()) {
int j = iter.nextInt();
if (vars[i].getLB().contains(j)) {
nbSameInKer++;
} else {
diff = j;
}
}
if (nbSameInKer == s) {
if (sei == s) { // check diff
fails(); // TODO: could be more precise, for explanation purpose
} else if (sei == s + 1 && ski < sei) { // force other (if same elements in ker)
iter = vars[i].getUB().iterator();
while (iter.hasNext())
vars[i].force(iter.nextInt(), this);
}
} else if (sei == s && nbSameInKer == s - 1) { // remove other (if same elements in ker)
if (vars[i].getUB().contains(diff)) {
vars[i].remove(diff, this);
}
}
}
}
}
}
}
@Override
public ESat isEntailed() {
for (int i = 0; i < n; i++) {
if (!vars[i].isInstantiated()) {
return ESat.UNDEFINED;
}
for (int i2 = i + 1; i2 < n; i2++) {
if (same(i, i2)) {
return ESat.FALSE;
}
}
}
return ESat.TRUE;
}
private boolean same(int i, int i2) {
if (vars[i].getUB().size() < vars[i2].getLB().size()) return false;
if (vars[i2].getUB().size() < vars[i].getLB().size()) return false;
if (vars[i].isInstantiated() && vars[i2].isInstantiated()) {
ISetIterator iter = vars[i].getLB().iterator();
while (iter.hasNext()){
if (!vars[i2].getUB().contains(iter.nextInt())) {
return false;
}
}
return true;
}
return false;
}
}