private List<Integer> extractParticipients(Assignment a) {
List<Integer> participients = new ArrayList<>(a.assignedVariables());
Collections.sort(participients);
return participients;
}
public List<KAryConstraint> collectAllSubConstraints(Assignment a) {
LinkedList<KAryConstraint> ret = new LinkedList<>();
_collectAllSubConstraints(a.assignedVariables(), ret);
return ret;
}