图_邻接表的操作

public int getDegree(int i){
		VNode v = vexs[i];
		int count = 0;
		//入度
		for(ArcNode arc = v.firstArc;arc!=null;arc = arc.nextArc)
			count++;
		//出度
		for(VNode u: vexs)
			for(ArcNode arc = u.firstArc;arc!=null;arc= arc.nextArc)
				if(vexs[arc.adjVex].equals(v))
					count++;
			return count;
	}