红黑二叉树实现代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace winterHomework
{
    //算法思路 http://blog.csdn.net/goodluckwhh/article/details/11804733 + http://blog.csdn.net/kartorz/article/details/8865997
    public class TreeNode<T>
    {
        public int data { set; get; }
        public string color { set; get; }
        public TreeNode<T> father { get; set; }
        public TreeNode<T> leftChild { set; get; }
        public TreeNode<T> rightChild { set; get; }

        public TreeNode(int item)
        {
            this.data = item;
            this.leftChild = null;
            this.rightChild = null;
            this.color = "red";
        }
        public TreeNode()
        {
            this.data = default(int);
            this.leftChild = null;
            this.rightChild = null;
            this.color = "red";

        }

    }
    public class RBTree<T>
    {
        public TreeNode<T> root { set; get; }
        public RBTree()
        {
            root = null;
        }
        public TreeNode<T> CreateNewNode(int item){
            TreeNode<T> newNode = new TreeNode<T>(item);
            return newNode;
        }
        public TreeNode<T> AppendNode(TreeNode<T> newNode)
        {
            //要插入的节点
            if (root == null)
            {
                root = newNode;
                root.color = "black";
                return root;
            }
            //找到要插入的位置
            TreeNode<T> traversal = root;
            bool insertSuccess=false;
            while (!insertSuccess)
            {
                if (newNode.data > traversal.data) {
                    if ( traversal.rightChild != null)