c# 有序链表合并 链表反转

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

namespace LinkedListTest
{
    class Program
    {
        static void Main(string[] args)
        {

            LinkList<int> linkA = new LinkList<int>();
            linkA.Append(1);
            linkA.Append(3);
            linkA.Append(5);
            linkA.Append(7);
            linkA.Append(9);

            LinkList<int> linkB = new LinkList<int>();
            linkB.Append(0);
            linkB.Append(2);
            linkB.Append(4);
            linkB.Append(6);
            linkB.Append(8);
            //合并有序链表
            Console.WriteLine("----------合并有序链表---------");
            Node<int> nodeMerge= Merge(linkA.Head, linkB.Head);
            LinkList<int> linkMerge = new LinkList<int>();
            linkMerge.Head = nodeMerge;
            linkMerge.Dispaly();

            //链表反转
            Console.WriteLine("----------链表反转---------");
            linkMerge.Reverse();
            Console.Read();
        }
        /// <summary>
        /// 链表合并
        /// </summary>
        /// <param name="nodeA"></param>
        /// <param name="nodeB"></param>
        /// <returns></returns>
        public static Node<int> Merge(Node<int> nodeA, Node<int> nodeB)
        {
            if (nodeA == null)
            {
                return nodeB;
            }
            else if (nodeB == null)
            {
                return nodeA;
            }

            Node<int> newHead = null;

            if (nodeA.Data <= nodeB.Data)
            {
                newHead = nodeA;
                newHead.Next = Merge(nodeA.Next, nodeB);
            }
            else
            {
                newHead = nodeB;
                newHead.Next = Merge(nodeA, nodeB.Next);
            }

            return newHead;
        }

    }
    public class LinkList<T>
    {
        public Node<T> Head { set; get; } //单链表头

        //构造
        public LinkList()
        {
            Clear();
        }

        /// <summary>
        /// 求单链表的长度
        /// </summary>
        /// <returns></returns>
        public int GetLength()
        {
            Node<T> p = Head;
            int length = 0;
            while (p != null)
            {
                p = p.Next;
                length++;
            }
            return length;
        }

        /// <summary>
        /// 判断单键表是否为空
        /// </summary>
        /// <returns></returns>
        public bool IsEmpty()
        {
            if (Head == null)
                return true;
            else
                return false;
        }

        /// <summary>
        /// 清空单链表
        /// </summary>
        public void Clear()
        {
            Head = null;
        }

        /// <summary>
        /// 获得当前位置单链表中结点的值
        /// </summary>
        /// <param name="i">结点位置</param>
        /// <returns></returns>
        public T GetNodeValue(int i)
        {
            if (IsEmpty() || i < 1 || i > GetLength())
            {
                Console.WriteLine("单链表为空或结点位置有误！");
                return default(T);
            }

            Node<T> A = new Node<T>();
            A = Head;
            int j = 1;
            while (A.Next != null && j < i)
            {
                A = A.Next;
                j++;
            }

            return A.Data;
        }

        /// <summary>
        /// 增加新元素到单链表末尾
        /// </summary>
        public void Append(T item)
        {
            Node<T> foot = new Node<T>(item);
            Node<T> A = new Node<T>();
            if (Head == null)
            {
                Head = foot;
                return;
            }
            A = Head;
            while (A.Next != null)
            {
                A = A.Next;
            }
            A.Next = foot;
        }

        /// <summary>
        /// 增加单链表插入的位置
        /// </summary>
        /// <param name="item">结点内容</param>
        /// <param name="n">结点插入的位置</param>
        public void Insert(T item, int n)
        {
            if (IsEmpty() || n < 1 || n > GetLength())
            {
                Console.WriteLine("单链表为空或结点位置有误！");
                return;
            }

            if (n == 1)  //增加到头部
            {
                Node<T> H = new Node<T>(item);
                H.Next = Head;
                Head = H;
                return;
            }

            Node<T> A = new Node<T>();
            Node<T> B = new Node<T>();
            B = Head;
            int j = 1;
            while (B.Next != null && j < n)
            {
                A = B;
                B = B.Next;
                j++;
            }

            if (j == n)
            {
                Node<T> C = new Node<T>(item);
                A.Next = C;
                C.Next = B;
            }
        }

        /// <summary>
        /// 删除单链表结点
        /// </summary>
        /// <param name="i">删除结点位置</param>
        /// <returns></returns>
        public void Delete(int i)
        {
            if (IsEmpty() || i < 1 || i > GetLength())
            {
                Console.WriteLine("单链表为空或结点位置有误！");
                return;
            }

            Node<T> A = new Node<T>();
            if (i == 1)   //删除头
            {
                A = Head;
                Head = Head.Next;
                return;
            }
            Node<T> B = new Node<T>();
            B = Head;
            int j = 1;
            while (B.Next != null && j < i)
            {
                A = B;
                B = B.Next;
                j++;
            }
            if (j == i)
            {
                A.Next = B.Next;
            }
        }

        /// <summary>
        /// 显示单链表
        /// </summary>
        public void Dispaly()
        {
            Node<T> A = new Node<T>();
            A = Head;
            while (A != null)
            {
                Console.WriteLine(A.Data);
                A = A.Next;
            }
        }

        #region 面试题
        /// <summary>
        /// 单链表反转
        /// </summary>
        public void Reverse()
        {
            if (GetLength() == 1 || Head == null)
            {
                return;
            }

            Node<T> NewNode = null;
            Node<T> CurrentNode = Head;
            Node<T> TempNode = new Node<T>();

            while (CurrentNode != null)
            {
                TempNode = CurrentNode.Next;
                CurrentNode.Next = NewNode;
                NewNode = CurrentNode;
                CurrentNode = TempNode;
            }
            Head = NewNode;

            Dispaly();
        }

        /// <summary>
        /// 获得单链表中间值
        /// 思路：使用两个指针，第一个每次走一步，第二个每次走两步：
        /// </summary>
        public void GetMiddleValue()
        {
            Node<T> A = Head;
            Node<T> B = Head;

            while (B != null && B.Next != null)
            {
                A = A.Next;
                B = B.Next.Next;
            }
            if (B != null) //奇数
            {
                Console.WriteLine("奇数:中间值为：{0}", A.Data);
            }
            else    //偶数
            {
                Console.WriteLine("偶数:中间值为：{0}和{1}", A.Data, A.Next.Data);
            }
        }

        #endregion

    }

    public class Node<T>
    {
        public T Data { set; get; }          //数据域,当前结点数据
        public Node<T> Next { set; get; }    //位置域,下一个结点地址

        public Node(T item)
        {
            this.Data = item;
            this.Next = null;
        }

        public Node()
        {
            this.Data = default(T);
            this.Next = null;
        }
    }
}