数据结构-双向链表&双向循环链表

时间 2019-12-01 标签数据结构双向链表双向循环链表

借图：http://www.cnblogs.com/skywang12345/p/3561803.html#a33

双向链表

双向链表(双链表)是链表的一种。和单链表同样，双链表也是由节点组成，它的每一个数据结点中都有两个指针，分别指向直接后继和直接前驱。html

实现：接口ide

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

namespace _001_线性表
{
    interface IListDS<T>
    {
        int GetLength();
        void Clear();
        bool IsEmpty();
        void Add(T item);
        void Insert(T item, int index);
        T Delete(int index);
        T this[int index] { get; }
        T GetEle(int index);
        int Locate(T value);

    }
}

View Code

双向节点：oop

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

namespace _001_线性表
{
    /// <summary>
    /// 双向节点
    /// </summary>
    /// <typeparam name="T"></typeparam>
    class DbNode<T>
    {
        private T data;
        private DbNode<T> prev;
        private DbNode<T> next;

        public DbNode(T val,DbNode<T> p,DbNode<T> n)
      {
          this.data = val;
          this.prev = p;
          this.next = n;
      }
        public DbNode(DbNode<T> p)
        {
            next = p;
        }
        public DbNode(T val)
        {
            data = val;
            next = null;
            prev = null;
        }
        public DbNode()
        {
            data = default(T);
            next = null;
            prev = null;
        }
        public T Data
        {
            get { return data; }
            set { data = value; }
        }
        public DbNode<T> Prev
        {
            get { return prev; }
            set { prev = value; }
        }
        public DbNode<T> Next
        {
            get { return next; }
            set { next = value; }
        }
        public void SetNode(DbNode<T> pre,DbNode<T> next)
        {
            this.prev = pre;
            this.next = next;
        }



    }
}

View Code

双向链表：this

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

namespace _001_线性表
{
    /// <summary>
    /// 双向链表
    /// </summary>
    /// <typeparam name="T"></typeparam>
    class DoubleLink<T>:IListDS<T>
    {
        #region IListDS<T> 成员

        private DbNode<T> _linkHead;
        public DoubleLink()
        {
            _linkHead = null;
        }
       
        public int GetLength()
        {
            if (IsEmpty()) return 0;
            DbNode<T> temp = _linkHead;
            int length = 1;
            while (temp.Next != null)
            {
                 length++;
                 temp = temp.Next;
            }
            return length;
        }

        public void Clear()
        {
            _linkHead = null;
        }

        public bool IsEmpty()
        {
            return _linkHead == null;
        }

        /// <summary>
        /// 在双向链表的尾端添加一个新数据
        /// </summary>
        /// <param name="item"></param>
        public void Add(T item)
        {
            DbNode<T> newNode = new DbNode<T>(item);
            if (IsEmpty())
            {
                _linkHead = newNode;
            }
            else
            {
                DbNode<T> preNode = GetListItem(this.GetLength() - 1);
                newNode.Prev = newNode;
                preNode.Next = newNode.Prev;
                newNode.Prev = preNode;
            }
        }

        /// <summary>
        /// 获取指定位置的双向链表项目，头项从0开始
        /// </summary>
        public DbNode<T> GetListItem(int index)
        {
            if (index < 0)
                throw new Exception("索引不能小于0");
            if (index > this.GetLength() - 1)
                throw new Exception("索引超出列表总长度");
            DbNode<T> temp = _linkHead;
            for (int i = 0; i < index; i++)
            {
                temp = temp.Next;
            }
            return temp;
        }

        /// <summary>
        /// 在双向链表指定的位置插入一个新项
        /// </summary>
        public void Insert(T item, int index)
        {
            if (index < 0)
                throw new Exception("插入位置不能小于0");
            if (index > this.GetLength() + 1)
                throw new Exception("插入位置超出链表长度");
            DbNode<T> newNode = new DbNode<T>(item);
            if (index == 0)
            {
                newNode.Next = _linkHead;
                _linkHead = newNode;
            }
            else
            {
                DbNode<T> preNode = GetListItem(index - 1); //要插入位置前面的节点
                DbNode<T> atfNode = GetListItem(index);//要插入位置后面的节点
                preNode.Next = new DbNode<T>(item, preNode, atfNode);
            }
        }


        /// <summary>
        /// 删除指定位置的双向链表项
        /// </summary>
        /// <param name="index"></param>
        public T Delete(int index)
        {
            if (index < 0)
                throw new Exception("删除位置不能小于0");
            if (index > this.GetLength() - 1)
                throw new Exception("插入位置超出链表长度");

            T data = default(T);
            if (index == 0)
            {
                data = _linkHead.Data;
                _linkHead = _linkHead.Next;
                if(!IsEmpty())
                    this._linkHead.Prev = null;
            }
            else
            {
                DbNode<T> DelNode = GetListItem(index); //取到要删除的节点
                data = DelNode.Data;
                DbNode<T> preNode = DelNode.Prev;
                DbNode<T> nextNode = DelNode.Next;
                preNode.Next = nextNode;
                nextNode.Prev = preNode;
            }
            return data;
        }

        public T this[int index]
        {
            get { return GetEle(index); }
        }

        public T GetEle(int index)
        {
            DbNode<T> temp = _linkHead;
            for (int i = 0; i < index; i++)
            {
                temp = temp.Next;
            }
            return temp.Data;
        }

        public int Locate(T value)
        {
            DbNode<T> temp = _linkHead;
            if (IsEmpty())
            {
                return -1;
            }
            else
            {
                int index = 0;
                while (true)
                {
                    if (!temp.Data.Equals(value))
                    {
                        if (temp.Next != null)
                        {
                            index++;
                            temp = temp.Next;
                        }
                        else
                        {
                            break;
                        }
                    }
                    else
                    {
                        return index;
                    }
                }
                return -1;
            }
        }
        #endregion
    }
}

双向循环链表

从双向链表中的任意一个结点开始，均可以很方便地访问它的前驱结点和后继结点。通常咱们都构造双向循环链表。spa

双链表的示意图以下：指针

表头为空，表头的后继节点为"节点10"(数据为10的节点)；"节点10"的后继节点是"节点20"(数据为10的节点)，"节点20"的前继节点是"节点10"；"节点20"的后继节点是"节点30"，"节点30"的前继节点是"节点20"；...；末尾节点的后继节点是表头。code

双链表删除节点

删除"节点30"
删除以前："节点20"的后继节点为"节点30"，"节点30" 的前继节点为"节点20"。"节点30"的后继节点为"节点40"，"节点40" 的前继节点为"节点30"。
删除以后："节点20"的后继节点为"节点40"，"节点40" 的前继节点为"节点20"。htm

双链表添加节点

在"节点10"与"节点20"之间添加"节点15"
添加以前："节点10"的后继节点为"节点20"，"节点20" 的前继节点为"节点10"。
添加以后："节点10"的后继节点为"节点15"，"节点15" 的前继节点为"节点10"。"节点15"的后继节点为"节点20"，"节点20" 的前继节点为"节点15"。blog

实现：索引

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

namespace _001_线性表
{
    /// <summary>
    /// 双向循环链表
    /// </summary>
    /// <typeparam name="T"></typeparam>
    class DoubleLoopLink<T> : IListDS<T>
    {
        private DbNode<T> _linkHead;
        public T this[int index] =>GetEle(index);

        public void Add(T item)
        {
            DbNode<T> newNode = new DbNode<T>(item, null, null);
            if (IsEmpty())
            {
                _linkHead = newNode;
                _linkHead.Prev = _linkHead;
                _linkHead.Next = _linkHead;
            }
            else
            {
                DbNode<T> preNode = _linkHead;
                while (preNode.Next != _linkHead)
                {
                    preNode = preNode.Next;
                }
                preNode.Next = newNode;//链表的尾部 的后指针  指向新的节点
                newNode.SetNode(preNode, _linkHead);     
                _linkHead.Prev = newNode; //头部的 前指针 指向 新的尾部
            }
        }
        
        public void Clear()
        {
            _linkHead = null;
        }

        public T Delete(int index)
        {
            T data = default(T);
            if (IsEmpty())
                throw new Exception("链表为空，没有可清除的项");
            if (index < 0 || index > this.GetLength() - 1)
                throw new Exception("给定索引超出链表长度");

            DbNode<T> preNode = _linkHead;
            if (index == 0)
            {
                while (preNode.Next != _linkHead)
                {
                    preNode = preNode.Next;
                }
                this._linkHead = _linkHead.Next;
                this._linkHead.Prev = preNode;
                data = preNode.Next.Data;
                preNode.Next = this._linkHead;
            }
            else
            {
                for (int i = 1; i < index - 1; i++)
                {
                    preNode = preNode.Next;
                }
                //看图比较好理解
                DbNode<T> aftNode = preNode.Next.Next; //要删除的节点  后面的节点
                preNode.Next = aftNode;//要删除节点的前面节点 的后指针 指向  要删除的节点  后面的节点
                aftNode.Prev = preNode; //要删除的节点 前面的节点  指向  要删除节点的前面节点    
            }
            return data;
        }

        public T GetEle(int index)
        {
            DbNode<T> temp = _linkHead;
            for (int i = 0; i < index; i++)
            {
                temp = temp.Next;
            }
            return temp.Data;
        }

        public int GetLength()
        {
            if (IsEmpty()) return 0;
            DbNode<T> temp = _linkHead;
            int length = 1;
            while (temp.Next != _linkHead)
            {
                length++;
                temp = temp.Next;
            }
            return length;
        }
        /// <summary>
        /// 插入
        /// </summary>
        /// <param name="item"></param>
        /// <param name="index"></param>
        public void Insert(T item, int index)
        {
            if (IsEmpty())
                throw new Exception("数据链表为空");
            if (index < 0 || index > this.GetLength())
                throw new Exception("给定索引超出链表长度");

            DbNode<T> newNode = new DbNode<T>(item);
            DbNode<T> preNode = _linkHead;
            if (index == 0) //等于零  先找到 链表中 head的前一个节点 这个节点链接 head
            {
                while (preNode.Next != _linkHead)
                {
                    preNode = preNode.Next;
                }
                preNode.Next = newNode;
                newNode.SetNode(preNode, _linkHead);
                _linkHead.Prev = newNode;
                return;
            }
            else
            {
                for (int i = 1; i < index - 1; i++)
                {
                    preNode = preNode.Next;
                }
                //preNode要插入位置的前节点
                DbNode<T> atfNode = preNode.Next;//要插入节点的后节点
                preNode.Next = newNode; //后指针 连上新节点
                newNode.SetNode(preNode,atfNode);
                atfNode.Prev = newNode;//要插入节点的后节点 连上 新节点
            }
        }
        public bool IsEmpty()
        {
            return _linkHead == null;
        }

        public int Locate(T value)
        {
            if (IsEmpty())
                throw new Exception("链表为空");
            DbNode<T> preNode = _linkHead;
            int index = 0;
            while (true)
            {
                if (!preNode.Data.Equals(value))
                {
                    if (preNode.Next != _linkHead)
                    {
                        index++;
                        preNode = preNode.Next;
                    }
                    else
                    {
                        break;
                    }
                }
                else
                {
                    return index;
                }
            }
            return -1;
        }
    }
}

View Code

基本的链表大概就是这样了。