题解 | #二叉树的中序遍历#

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整型一维数组
     */
    public List<int> inorderTraversal (TreeNode root) {
        List<int> list = new List<int>();
        abcd(root, list);
        return list;
    }

    public void abcd(TreeNode root, List<int> list){
        if(root == null){
            return;
        }        
        abcd(root.left, list);
        list.Add(root.val);
        abcd(root.right, list);
    }
}