摇摆打印二叉树

//树节点
public class TreeNode {
        int val = 0;
        TreeNode left = null;
        TreeNode right = null;

        public TreeNode(int val) {
            this.val = val;

        }
    }
public ArrayList<ArrayList<Integer> > Print(TreeNode pRoot) {
        /*
        层次遍历：队列
        奇数行：左——>右
        偶数行：右->左（奇数行的逆序）
         */
        ArrayList<ArrayList<Integer>> allList = new ArrayList<ArrayList<Integer>>();
        if(pRoot==null){
            return null;
        }
        Queue<TreeNode>[] queue = new Queue[2];
        queue[0] = new ArrayDeque<>();//奇数行
        queue[1] = new ArrayDeque<>();//偶数行
        int count=1; //记录当前到达的层数
        queue[1].add(pRoot);
        while(!queue[0].isEmpty() || !queue[1].isEmpty()){
            ArrayList<Integer> list = new ArrayList<>();
            while(!queue[count%2].isEmpty()){
                TreeNode temp = queue[count%2].poll();
                list.add(temp.val);
                if(temp.left!=null){
                    queue[(count+1)%2].add(temp.left);
                }
                if(temp.right!=null){
                    queue[(count+1)%2].add(temp.right);
                }
            }
　　　　　　　//偶数行:翻转序列
            if(count%2==0){
                Collections.reverse(list);
            }
            allList.add(list);
            count++;
        }
        return allList;
    }