candidates    = new int[dimPersons];
  public Solver(int dimTopics, int dimPersons, int dimRoles, int dimSessions)  {    this.dimSessions = dimSessions;    topics        = new Topics(this, dimTopics);    persons       = new Persons(this, dimPersons, dimTopics);    roles         = new Roles(dimRoles, dimPersons, dimSessions);    solutions     = new Vector();    solutionNames = new DefaultListModel();  }