数据结构-二叉排序树

 

 结点类代码实现：

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

namespace _013_二叉树
{
    class BsNode
    {
        private BsNode LeftChild=null;
        private BsNode RightChild=null;
        private BsNode Parent=null;
        private int Data;
        internal BsNode rightChild { get => RightChild; set => RightChild = value; }
        internal BsNode leftChild { get => LeftChild; set => LeftChild = value; }
        internal BsNode parent { get => Parent; set => Parent = value; }
        internal int data { get => Data; set => Data = value; }

        public BsNode()
        {

        }
        public BsNode(int item)
        {
            this.data = item;
        }

   
    }
}

排序树代码实现：

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

namespace _013_二叉树
{
    /// <summary>
    /// 二叉排序树
    /// </summary>
    class BsTree
    {
        private BsNode RootNode = null;


        /// <summary>
        /// 添加数据
        /// </summary>
        /// <param name="item"></param>
        public void Add(int item)
        {
            BsNode newNode = new BsNode(item);
            if (RootNode == null)//空树
                RootNode = newNode;
            else
            {
                BsNode temp = RootNode;
                while (true)
                {
                    if (item >= temp.data)//放在temp的右边
                    {
                        if (temp.rightChild == null) //如果右边为空  就直接添加
                        {
                            temp.rightChild =  newNode;
                            newNode.parent = temp;
                            break;
                        }
                        else //不为空 ，就赋值继续查找
                        {
                            temp = temp.rightChild;
                        }
                    }
                    else //放在temp的左边
                    {
                        if (temp.leftChild == null) //如果左边为空  就直接添加
                        {
                            temp.leftChild = newNode;
                            newNode.parent = temp;
                            break;
                        }
                        else//不为空 ，就赋值继续查找
                        {
                            temp = temp.leftChild;
                        }
                    }
                }
            }
        }
        /// <summary>
        /// 查找
        /// </summary>
        /// <param name="item"></param>
        /// <returns></returns>
        public bool Find(int item)
        {
            //return Find(item, RootNode);

            //方法二
            BsNode temp = RootNode;
            while (true)
            {
                if (temp == null) return false;
                if (temp.data == item) return true;
                if (temp.data < item)
                {
                    temp = temp.rightChild;
                }
                else
                {
                    temp = temp.leftChild;
                }
            }
        }
        /// <summary>
        /// 查找方法1
        /// </summary>
        /// <param name="item"></param>
        /// <param name="node"></param>
        /// <returns></returns>
        public bool Find(int item,BsNode node)
        {
            if (node == null) return false;
            if (node.data == item) return true;
            else
            {
                if (item > node.data)
                {
                   return Find(item, node.rightChild);
                }
                else
                {
                    return  Find(item, node.leftChild);
                }
            }
        }
        public void MiddleTraversal()
        {
            MiddleTraversal(RootNode);
        }
        /// <summary>
        /// 中序遍历
        /// </summary>
        /// <param name="node"></param>
        private void MiddleTraversal(BsNode node)
        {
            if (node == null) return;

            MiddleTraversal(node.leftChild);
            Console.Write(node.data+" ");
            MiddleTraversal(node.rightChild);
        }

        public bool Delete(int item)
        {
            BsNode temp = RootNode;
            while (true)
            {
                if (temp == null) return false;
                if (temp.data == item)
                {
                    Delete(temp);
                    return true;
                }
                if (temp.data < item)
                {
                    temp = temp.rightChild;
                }
                else
                {
                    temp = temp.leftChild;
                }
            }
        }
        private void Delete(BsNode node)
        {
            //第一种情况 删除叶子结点
            if(node.leftChild == null && node.rightChild==null)
            {
                if (node.parent == null)
                {
                    RootNode = null;
                }
                if (node.parent.leftChild == node)
                {
                    node.parent.leftChild = null;
                }
                else if(node.parent.rightChild == node)
                {
                    node.parent.rightChild = null;
                }
                return;
            }

            // 第二种情况 仅有左子树或者右子数的结点
            if (node.leftChild==null && node.rightChild != null)
            {
                node.data = node.rightChild.data;
                node.rightChild =null;
                return;
            }
            if (node.leftChild != null && node.rightChild == null)
            {
                node.data = node.leftChild.data;
                node.leftChild = null;
                return;
            }

            //第三种情况 左右子树都有节点
            BsNode temp = node.rightChild;
            while (temp.leftChild != null)
            {
                    temp = temp.leftChild;
            }
            node.data = temp.data;
            Delete(temp);
        }
    }
}