单链表

单链表封装

function LinkedList(){
    function Node(data){
        this.data = data;
        this.next = null;
    }
    this.head = null;
    this.length = 0;
}

向尾部添加

LinkedList.prototype.append = function(data) {
    var newNode = new Node(data);
    // 判断是否是第一个节点
    if (this.length == 0) {    
        // 首节点为第一个加入的元素
        this.head = newNode;
    }else {
        var current = this.head;
        // 找到最后一个节点
        while (current.next) {
            current = current.next;
        }
        // 最后一个节点指向新加入元素
        current.next = newNode;
    }

    this.length += 1
}

toString

LinkedList.prototype.toString = function() {
    var current = this.head;
    let str = '';

    while(current){
        str += current.data;
        current = current.next;
    }
    return str;
}

添加到指定位置

LinkedList.prototype.insert = function(position,data) {
    // 判断position越界
    if (position < 0 || position > this.length) {
        return false;
    }
    var newNode = new Node(data);
    var current = this.head;

    if (position == 0) {
        newNode.next = this.head;
        this.head = newNode;
    } else {
        var index = 0;
        var current = this.head;
        // 获取添加位置前的那个节点
        var previous = null;
        while(index++ < position){
            previous = current;
            current = current.next;
        }
        newNode.next = current;
        previous.next = newNode;
    }
    this.length += 1;
}

获取对应位置的元素

LinkedList.prototype.get = function(position) {
    if (position < 0 || position >= this.length) {
        return
    }

    var current = this.head;
    var index = 0;
    while(current++ < position){
        current = current.next;
    }
    return current.data;
}

返回元素在列表中的索引

LinkedList.prototype.indexOf = function(data) {
    var current = this.head;
    var index = 0;

    while (current) {
        // 判断数据是否相同
        if (current.data == data) {
            return index;
        }
        // 向后遍历
        current = current.next;
        index++
    }

    return -1;

}

更新对应位置的元素

LinkedList.prototype.update = function(position,newData) {
    if (position < 0 || position >= this.length) {
        return
    }
    var current = this.head;
    var index = 0;
    while(current++ < position){
        current = current.next;
    }
    current.data = newData;
}

移除特定位置

LinkedList.prototype.removeAt = function(position){
    if (position < 0 || position >= this.length) {
        return
    }
    if (position == 0) {
        this.head = this.head.next;
    }else {
        var index = 0;
        var current = this.head;
        var previous = null;
        while(index++ < position){
            previous = current;
            current = current.next;
        }
        previous.next = current.next;
    }
    this.length -= 1;
}

移除某项

LinkedList.prototype.remove = function(data){
    var position = this.indexOf(data);
    this.removeAt(position)
}