c#二叉树的层次遍历实现方法

下面是一个C#实现二叉树的层次遍历的例子：

using System;using System.Collections.Generic;public class TreeNode {    public int val;    public TreeNode left;    public TreeNode right;    public TreeNode(int val = 0, TreeNode left = null, TreeNode right = null) {        this.val = val;        this.left = left;        this.right = right;    }}public class BinaryTree {    public List<List<int>> LevelOrder(TreeNode root) {        List<List<int>> result = new List<List<int>>();        if (root == null) {            return result;        }        Queue<TreeNode> queue = new Queue<TreeNode>();        queue.Enqueue(root);        while (queue.Count > 0) {            int levelSize = queue.Count;            List<int> levelValues = new List<int>();            for (int i = 0; i < levelSize; i++) {                TreeNode node = queue.Dequeue();                levelValues.Add(node.val);                if (node.left != null) {                    queue.Enqueue(node.left);                }                if (node.right != null) {                    queue.Enqueue(node.right);                }            }            result.Add(levelValues);        }        return result;    }}class Program {    static void Main() {        TreeNode root = new TreeNode(3);        root.left = new TreeNode(9);        root.right = new TreeNode(20);        root.right.left = new TreeNode(15);        root.right.right = new TreeNode(7);        BinaryTree bt = new BinaryTree();        List<List<int>> result = bt.LevelOrder(root);        foreach (List<int> level in result) {            Console.Write("[");            foreach (int val in level) {                Console.Write(val + " ");            }            Console.Write("]");            Console.WriteLine();        }    }}

这段代码实现了一个二叉树的层次遍历。通过使用一个队列来辅助遍历，每次遍历一层节点，依次将它们的值存入结果列表中。最后返回结果列表。在Main函数中创建一个二叉树节点并调用LevelOrder方法进行层次遍历。