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* Copyright (c) 1999-2014, Ecole des Mines de Nantes
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*
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package solver.constraints.nary.alldifferent;
import solver.constraints.Constraint;
import solver.constraints.Propagator;
import solver.constraints.binary.PropNotEqualX_Y;
import solver.constraints.nary.cnf.PropTrue;
import solver.variables.IntVar;
/**
* Ensures that all variables from VARS take a different value.
* The consistency level should be chosen among "AC", "BC", "FC" and "DEFAULT".
*/
public class AllDifferent extends Constraint {
public static enum Type {
AC, BC, FC, NEQS, DEFAULT
}
public AllDifferent(IntVar[] vars, String type) {
super("AllDifferent",createPropagators(vars, type));
}
private static Propagator<IntVar>[] createPropagators(IntVar[] VARS, String consistency) {
if(VARS.length<=1){
return new Propagator[]{new PropTrue(VARS[0].getSolver().ONE)};
}
switch (AllDifferent.Type.valueOf(consistency)) {
case NEQS: {
int s = VARS.length;
int k = 0;
Propagator[] props = new Propagator[(s * s - s) / 2];
for (int i = 0; i < s - 1; i++) {
for (int j = i + 1; j < s; j++) {
props[k++] = new PropNotEqualX_Y(VARS[i], VARS[j]);
}
}
return props;
}
case FC: return new Propagator[]{new PropAllDiffInst(VARS)};
case BC: return new Propagator[]{new PropAllDiffInst(VARS), new PropAllDiffBC(VARS)};
case AC: return new Propagator[]{new PropAllDiffInst(VARS), new PropAllDiffAC(VARS)};
case DEFAULT:
default:
// adds a Probabilistic AC (only if at least some variables have an enumerated domain)
boolean enumDom = false;
for (int i = 0; i < VARS.length && !enumDom; i++) {
if (VARS[i].hasEnumeratedDomain()) {
enumDom = true;
}
}
if (enumDom) {
return new Propagator[]{new PropAllDiffInst(VARS), new PropAllDiffBC(VARS), new PropAllDiffAdaptative(VARS)};
} else {
return createPropagators(VARS,"BC");
}
}
}
}