题解 | #求二叉树的层序遍历#

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 root TreeNode类 
     * @return int整型二维数组
     */
    public List<List<int>> levelOrder (TreeNode root) {
        Queue<TreeNode> que = new Queue<TreeNode>();
        List<List<int>> bigList = new List<List<int>>();
        if(root == null) return bigList;
        que.Enqueue(root);
        while(que.Count != 0){
            List<int> smallList = new List<int>();
            for(int len = que.Count; len > 0; len--){
                TreeNode cur = que.Dequeue();
                smallList.Add(cur.val);
                if(cur.left != null)que.Enqueue(cur.left);
                if(cur.right != null)que.Enqueue(cur.right);
            }
            bigList.Add(smallList);
        }
        return bigList;
    }
}