leetcode-94-二叉树的中序遍历

https://leetcode.cn/problems/binary-tree-inorder-traversal/

public class Solution {
    public IList InorderTraversal(TreeNode root)
        {
            IList listResult = new List();
            AddData2Node(root, listResult);
            return listResult;
        }

        private void AddData2Node(TreeNode root, IList listResult)
        {
            if (root == null)
            {
                return;
            }
            if (root.left != null)
            {
                AddData2Node(root.left, listResult);
            }
            listResult.Add(root.val);
            if (root.right != null)
            {
                AddData2Node(root.right, listResult);
            }
        }
}