js实现双向链表, 双向链表需要增加一个previous属性

双向链表,

双向链表需要增加一个previous属性

/*双向链表

* */

function Node(element) {

    this.element = element;

    this.next = null;

    this.previous = null;//双向链表在这里需要增加一个previous属性

}

function LList() {

    this.head = new Node("head");

    this.find = find;

    this.insert = insert;

    this.display = display;

    this.remove = remove;

    this.findLast = findLast;

    this.dispReverse = dispReverse;//将链表反转

}

function dispReverse() {

    var currNode = this.head;

    currNode = this.findLast();

    var nodestr = "";

    while (!(currNode.previous == null)) {

        nodestr += " "+currNode.element;

        currNode = currNode.previous;

    }

    console.log("将链表反转后： "+nodestr);

}

function findLast() {

    var currNode = this.head;

    while (!(currNode.next == null)) {

        currNode = currNode.next;

    }

    return currNode;

}

function remove(item) {

    var currNode = this.find(item);

    if (!(currNode.next == null)) {

        currNode.previous.next = currNode.next;

        currNode.next.previous = currNode.previous;

        currNode.next = null;

        currNode.previous = null;

    }

}

// findPrevious is no longer needed

/*function findPrevious(item) {

 var currNode = this.head;

 while (!(currNode.next == null) &&

 (currNode.next.element != item)) {

 currNode = currNode.next;

 }

 return currNode;

 }*/

function display() {

    var currNode = this.head;

    var nodestr = "";

    while (!(currNode.next == null)) {

        nodestr += " "+currNode.next.element;

        currNode = currNode.next;

    }

    console.log(nodestr);

}

function find(item) {

    var currNode = this.head;

    while (currNode.element != item) {

        currNode = currNode.next;

    }

    return currNode;

}

function insert(newElement, item) {

    var newNode = new Node(newElement);

    var current = this.find(item);

    newNode.next = current.next;

    newNode.previous = current;//双向链表在这里需要设置新节点previous属性

    current.next = newNode;

}

var cities = new LList();

cities.insert("Conway", "head");

cities.insert("Russellville", "Conway");

cities.insert("Carlisle", "Russellville");

cities.insert("Alma", "Carlisle");

cities.display();//Conway Russellville Carlisle Alma

cities.remove("Carlisle");

cities.display();//Conway Russellville Alma

cities.dispReverse();// Alma Russellville Conway