JS-常用的数据结构之链表的实现

  1 function LinkedList(){
  2     var Node = function(element){
  3         this.element = element;
  4         this.next = null;
  5     };
  6     
  7     var length = 0;
  8     var head = null
  9    
 10     this.append = function(element){
 11        // 创建一个节点
 12        var node = new Node(element);
 13        var current = null;
 14        
 15        if (head == null){
 16            head = node;
 17        }else{
 18            current = head;
 19            while(current.next){
 20                current = current.next;
 21            }
 22            //找到最后一项，将其next赋为node，建立连接
 23            current.next = node;
 24        }
 25        length++;
 26     } //向链表尾部添加一个新的项
 27 
 28     this.insert = function (position, element) {
 29         // 检查越界
 30         if(position >= 0 && position < length){
 31             var node = new Node(element);
 32             var current = head;
 33             var previous = null
 34             var index = 0
 35  
 36             if(position === 0){
 37                 node.next = current;
 38                 head = node;
 39             }else{
 40                 // 1 从前往后遍历找到position
 41                 while(index < position){
 42                    previous = current;
 43                    current = previous.next;
 44                    index++;
 45                 }
 46 
 47                 //通过改变指针，将node链接在previous和current之间
 48                 previous.next = node;
 49                 node.next = current;
 50                
 51                 // 2 经验证1和2没有区别
 52                 //while (index++ < position) {
 53                 //    previous = current;
 54                 //    current = current.next;
 55                 //}
 56                 //通过改变指针，将node链接在previous和current之间
 57                 //node.next = current;
 58                 //previous.next = node;
 59                 return true;
 60             }
 61         }else{
 62             return false;
 63         }
 64     }; //向链表特定位置插入一个新的项
 65 
 66     this.removeAt = function (position) {
 67         if(position > -1 && position < length){
 68             var current = head;
 69             var previous = null;
 70             var index = 0;
 71 
 72             if (position == 0){
 73                 head = current.next;
 74             }else{
 75                 while(index < position){
 76                     previous = current;
 77                     current = current.next;
 78                     index++;
 79                 }
 80                 previous.next = current.next;
 81             }
 82             length--;
 83             return current.element;
 84         }else{
 85             return null;
 86         }
 87     }; //从链表特定位置移除一项
 88     this.remove = function (element) {
 89         var index = this.indexOf(element);
 90         this.removeAt(index);
 91     }; //从链表中移除一项
 92     this.indexOf = function (element) {
 93         var current = head;
 94         var index = 0;
 95         while(current){
 96             if (current.element === element){
 97                 return index;
 98             }
 99             current = current.next;
100             index++;
101         }
102         return -1; 
103     }; //返回元素在链表中的索引，如果没有则返回-1
104     this.isEmpty = function () {
105         return length === 0;
106     }; //判断链表是否为空
107     this.size = function () {
108         return length;
109     }; //返回链表包含元素个数
110     this.getHead = function () {
111         return head;
112     }; //返回链表第一个元素
113     this.toString = function () {
114         var current = head;
115         var str = "";
116         while(current){
117             current = current.next;
118             str += "," + current.element;
119         }
120         return str.slice(1);
121     }; //只输出元素的值
122     this.print = function () {
123         console.log(this.toString());
124     }; //打印元素的值
125 }