题解 | #按之字形顺序打印二叉树#

using System;
using System.Collections.Generic;

/*
public class TreeNode
{
	public int val;
	public TreeNode left;
	public TreeNode right;

	public TreeNode (int x)
	{
		val = x;
	}
}
*/

class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pRoot TreeNode类 
     * @return int整型二维数组
     */
    public List<List<int>> Print (TreeNode pRoot) {
        List<List<int>> res = new List<List<int>>();
        Queue<TreeNode> que = new Queue<TreeNode>();
        if(pRoot != null) que.Enqueue(pRoot);
        bool needReverse = false;
        while(que.Count != 0){
            List<int> curList = new List<int>();
            for(int i = que.Count; i > 0; i--){
                TreeNode cur = que.Dequeue();
                curList.Add(cur.val);
                if(cur.left != null) que.Enqueue(cur.left);
                if(cur.right != null) que.Enqueue(cur.right);
            }
            if(needReverse) curList.Reverse();
            needReverse = !needReverse;
            res.Add(curList);
        }
        return res;
    }
}