C#實現二叉排序樹（鏈式存儲）

1、創建BSNode類。

namespace Algorithm
{
    public class BSNode
    {
        public int data;
        public BSNode leftChild=null;
        public BSNode rightChild=null;
        public BSNode parent=null;

        public BSNode(int data)
        {
            this.data = data;
        }
    }
}

2、創建BSTree類,實現添加，查找與刪除功能。

using System.Collections.Generic;

namespace Algorithm
{
    public class BSTree
    {
        public BSNode root = null;

        public void Add(int item)
        {
            BSNode newNode = new BSNode(item);
            if (root == null)
            {
                root = newNode;
            }
            else
            {
                BSNode tempNode = root;
                while (true)
                {
                    if (item < tempNode.data)
                    {
                        if (tempNode.leftChild == null)
                        {
                            tempNode.leftChild = newNode;
                            newNode.parent = tempNode;
                            break;
                        }
                        tempNode = tempNode.leftChild;
                    }
                    else
                    {
                        if (tempNode.rightChild == null)
                        {
                            tempNode.rightChild = newNode;
                            newNode.parent = tempNode;
                            break;
                        }

                        tempNode = tempNode.rightChild;
                    }
                }
            }
        }

        public List<int> Sort()
        {
            tempList = new List<int>();
            SortNode(root);
            return tempList;
        }

        private List<int> tempList;

        private void SortNode(BSNode node)
        {
            if (node == null) return;
            SortNode(node.leftChild);
            tempList.Add(node.data);
            SortNode(node.rightChild);
        }

        public BSNode FindNode(int item)
        {
            BSNode tempNode = root;
            while (tempNode != null)
            {
                if (item < tempNode.data)
                {
                    tempNode = tempNode.leftChild;
                }
                else if (item > tempNode.data)
                {
                    tempNode = tempNode.rightChild;
                }
                else
                {
                    return tempNode;
                }
            }
            return null;
        }

        public bool DeleteNode(int item)
        {
            BSNode deleteNode = FindNode(item);
            return DeleteNode(deleteNode);
        }

        private bool DeleteNode(BSNode deleteNode)
        {
            if (deleteNode == null) return false;

            if (deleteNode.leftChild == null && deleteNode.rightChild == null)
            {
                if (deleteNode.parent == null)
                {
                    root = null;
                }
                else if (deleteNode.parent.leftChild == deleteNode)
                {
                    deleteNode.parent.leftChild = null;
                    deleteNode.parent = null;
                }
                else
                {
                    deleteNode.parent.rightChild = null;
                    deleteNode.parent = null;
                }
            }
            else if (deleteNode.leftChild == null && deleteNode.rightChild != null)
            {
                if (deleteNode.parent.leftChild == deleteNode)
                {
                    deleteNode.parent.leftChild = deleteNode.rightChild;
                    deleteNode.rightChild.parent = deleteNode.parent;
                }
                else
                {
                    deleteNode.parent.rightChild = deleteNode.rightChild;
                    deleteNode.rightChild.parent = deleteNode.parent;
                }
            }
            else if (deleteNode.leftChild != null && deleteNode.rightChild == null)
            {
                if (deleteNode.parent.leftChild == deleteNode)
                {
                    deleteNode.parent.leftChild = deleteNode.leftChild;
                    deleteNode.leftChild.parent = deleteNode.parent;
                }
                else
                {
                    deleteNode.parent.rightChild = deleteNode.leftChild;
                    deleteNode.leftChild.parent = deleteNode.parent;
                }
            }
            else
            {
                BSNode tempNode = GetMinNode(deleteNode.rightChild);
                deleteNode.data = tempNode.data;
                DeleteNode(tempNode);
            }
            return true;
        }

        private BSNode GetMinNode(BSNode node)
        {
            while (node.leftChild != null)
            {
                node = node.leftChild;
            }
            return node;
        }
    }
}