import org.cpsolver.exam.criteria.InstructorNotAvailableConflicts; //导入依赖的package包/类
public ExamAssignment(org.cpsolver.exam.model.Exam exam, ExamPlacement placement, Assignment<org.cpsolver.exam.model.Exam, ExamPlacement> assignment) {
    super(exam);
    if (placement!=null) {
        iNrDirectConflicts = (int)exam.getModel().getCriterion(StudentDirectConflicts.class).getValue(assignment, placement, null) +
        					 (int)exam.getModel().getCriterion(StudentNotAvailableConflicts.class).getValue(assignment, placement, null);
        iNrMoreThanTwoADayConflicts = (int)exam.getModel().getCriterion(StudentMoreThan2ADayConflicts.class).getValue(assignment, placement, null);
        iNrBackToBackConflicts = (int)exam.getModel().getCriterion(StudentBackToBackConflicts.class).getValue(assignment, placement, null);
        iNrDistanceBackToBackConflicts = (int)exam.getModel().getCriterion(StudentDistanceBackToBackConflicts.class).getValue(assignment, placement, null);
        iPeriodPenalty = (int)exam.getModel().getCriterion(PeriodPenalty.class).getValue(assignment, placement, null);
        iRoomSizePenalty = (int)exam.getModel().getCriterion(RoomSizePenalty.class).getValue(assignment, placement, null);
        iRoomSplitPenalty = (int)exam.getModel().getCriterion(RoomSplitPenalty.class).getValue(assignment, placement, null);
        iRotationPenalty = (int)exam.getModel().getCriterion(ExamRotationPenalty.class).getValue(assignment, placement, null);
        iRoomPenalty = (int)exam.getModel().getCriterion(RoomPenalty.class).getValue(assignment, placement, null);
        iNrInstructorDirectConflicts = (int)exam.getModel().getCriterion(InstructorDirectConflicts.class).getValue(assignment, placement, null) +
        		(int)exam.getModel().getCriterion(InstructorNotAvailableConflicts.class).getValue(assignment, placement, null);
        iNrInstructorMoreThanTwoADayConflicts = (int)exam.getModel().getCriterion(InstructorMoreThan2ADayConflicts.class).getValue(assignment, placement, null);
        iNrInstructorBackToBackConflicts = (int)exam.getModel().getCriterion(InstructorBackToBackConflicts.class).getValue(assignment, placement, null);
        iNrInstructorDistanceBackToBackConflicts = (int)exam.getModel().getCriterion(InstructorDistanceBackToBackConflicts.class).getValue(assignment, placement, null);
        iValue = placement.toDouble(assignment);
        iPeriodId = placement.getPeriod().getId();
        iPeriodIdx = placement.getPeriod().getIndex();
        iRooms = new TreeSet<ExamRoomInfo>();
        iPeriodPref = (exam.getPeriodPlacements().size()==1?PreferenceLevel.sRequired:PreferenceLevel.int2prolog(iPeriodPenalty));
        if (placement.getRoomPlacements()!=null) {
            boolean reqRoom = placement.getRoomPlacements().size()==exam.getRoomPlacements().size();
            for (Iterator i=placement.getRoomPlacements().iterator();i.hasNext();) {
                ExamRoomPlacement room = (ExamRoomPlacement)i.next();
                iRooms.add(new ExamRoomInfo(room.getRoom(), (reqRoom?PreferenceLevel.sIntLevelRequired:room.getPenalty(placement.getPeriod()))));
            }
        }
        MinMaxPreferenceCombination pc = new MinMaxPreferenceCombination();
        for (ExamDistributionConstraint dc: placement.variable().getDistributionConstraints()) {
            if (dc.isHard() || dc.isSatisfied(assignment)) continue;
            pc.addPreferenceInt(dc.getWeight());
        }
        iDistPref = pc.getPreferenceProlog(); 
    }
}