public LinkedList<Integer> getAdjList() {
		LinkedList<Integer> adjList = new LinkedList<Integer>();
		if(this.top != null) adjList.add(this.top);
		if(this.right != null) adjList.add(this.right);
		if(this.bottom != null) adjList.add(this.bottom);
		if(this.left != null) adjList.add(this.left);
		return adjList;
	}