public InterferenceGraph(int countRegs){
  interference=new ArrayList<IntSet>(countRegs);
  for (int i=0; i < countRegs; i++) {
    interference.add(SetFactory.makeInterferenceSet(countRegs));
  }
}

public InterferenceGraph ( int countRegs ) { interference = new ArrayList < IntSet > ( countRegs ) ; for ( int i = 0 ; i < countRegs ; i ++ ) { interference . add ( SetFactory . makeInterferenceSet ( countRegs ) ) ; } }
creates a new graph .
