js双向链表代码实现

coder@hu

已于 2022-02-11 11:53:50 修改

阅读量479

点赞数 1

分类专栏：数据结构和算法文章标签：链表 javascript 数据结构

于 2022-02-11 11:52:27 首次发布

本文链接：https://blog.youkuaiyun.com/hulover/article/details/122877432

版权

数据结构和算法专栏收录该内容

8 篇文章

订阅专栏

双向链表也叫双链表，是链表的一种，它的每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。所以，从双向链表中的任意一个结点开始，都可以很方便地访问它的前驱结点和后继结点。一般我们都构造双向循环链表。
在这里插入图片描述

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>双向链表</title>
</head>

<body>
    <script>
        function DoublyLinkedList() {
            this.head = null
            this.tail = null
            this.length = 0
        }
        function Node(data) {
            this.pre = null
            this.data = data
            this.next = null
        }
        //append向链表尾部添加节点
        DoublyLinkedList.prototype.append = function (data) {
            var newNode = new Node(data)
            if (this.length == 0) {
                this.head = newNode
                this.tail = newNode
            } else {
                newNode.pre = this.tail
                this.tail.next = newNode
                this.tail = newNode
            }
            this.length++
        }
        //insert根据位置插入节点
        DoublyLinkedList.prototype.insert = function (data, position) {
            if (position < 0 || position > this.length) return false
            var newNode = new Node(data)
            if (this.length == 0) {
                this.head = newNode
                this.tail = newNode
            } else {
                if (position == 0) {
                    newNode.next = this.head
                    this.head.pre = newNode
                    this.head = newNode
                } else if (position == this.length) {
                    newNode.pre = this.tail
                    this.tail.next = newNode
                    this.tail = newNode
                } else {
                    var current = this.head
                    var index = 0
                    while (index++ < position) {
                        current = current.next
                    }
                    newNode.next = current
                    newNode.pre = current.pre
                    current.pre.next = newNode
                    current.pre = newNode
                }
            }
            this.length++
            return true
        }
        //get 根据位置获取节点数据
        DoublyLinkedList.prototype.get = function (position) {
            if (position < 0 || position >= this.length) return false
            var index = 0
            var current = this.head
            if (index++ < position) {
                current = current.next
            }
            return current.data
        }
        //indexOf根据data,返回节点位置
        DoublyLinkedList.prototype.indexOf = function (data) {
            var current = this.head
            var index = 0
            while (current) {
                if (current.data == data) {
                    return index
                }
                current = current.next
                index++
            }
            return -1
        }
        //update找到节点，修改数据
        DoublyLinkedList.prototype.update = function (data, position) {
            if (position < 0 || position >= this.length) return false
            var current = this.head
            var index = 0
            while (index++ < position) {
                current = current.next
            }
            current.data = data
            return true
        }
        //removeAt方法,根据位置删除节点
        DoublyLinkedList.prototype.removeAt = function (position) {
            if (position < 0 || position >= this.length) return null
            var current = this.head
            if (this.length == 1) {
                this.head = null
                this.tail = null
            } else {
                if (position == 0) {
                    this.head.next.pre = null
                    this.head = this.head.next
                } else if (position == this.length - 1) {
                    this.tail.pre.next = null
                    this.tail = this.tail.pre
                } else {
                    var index = 0

                    while (index++ < position) {
                        current = current.next
                    }
                    current.pre.next = current.next
                    current.next.pre = current.pre
                }
            }
            this.length--
            return current.data
        }
        //romve方法，根据数据删除节点
        DoublyLinkedList.prototype.remove=function(data){
            var position=this.indexOf(data)
            return this.removeAt(position)
        }
        //isEmpty方法，判断链表是否为空
        DoublyLinkedList.prototype.isEmpty=function(){
            return this.length==0
        }
         //size方法，判断链表是否为空
         DoublyLinkedList.prototype.size=function(){
            return this.length
        }
        //getFirstData方法，获取第一个元素数据
        DoublyLinkedList.prototype.getFirstData=function(){
            return this.head.data
        }
        //getLastData方法，获取最后一个元素数据
        DoublyLinkedList.prototype.getLastData=function(){
            return this.tail.data
        }
        //forwardString方法,向前遍历数据
        DoublyLinkedList.prototype.forwardString = function () {
            var current = this.tail
            var resultString = ""
            while (current) {
                resultString += current.data + '_'
                current = current.pre
            }
            return resultString

        }
        //backwardString方法,向后遍历数据
        DoublyLinkedList.prototype.backwardString = function () {
            var current = this.head
            var resultString = ""
            while (current) {
                resultString += current.data + '_'
                current = current.next
            }
            return resultString
        }
        //toString方法
        DoublyLinkedList.prototype.toString = function () {
            return this.backwardString()
        }
        var dll = new DoublyLinkedList()
        dll.append('a')
        dll.append('b')
        dll.append('c')
        dll.append('d')
        dll.insert("aa", 1)
        dll.insert("dd", 5)
        console.log(dll)
        console.log(dll.backwardString())
        console.log(dll.indexOf('dd'))
        dll.update("cc", 3)
        dll.removeAt(0)
        dll.remove('dd')
        console.log(dll.toString())
        console.log(dll.get(2))
        console.log(dll.isEmpty())
        console.log(dll.size())
        console.log(dll.getFirstData())
        console.log(dll.getLastData())
    </script>
</body>

</html>

在这里插入图片描述