Node.js环境下JavaScript实现单链表与双链表结构
编程学习 2021-07-04 19:59www.dzhlxh.cn编程入门
Node环境下通过npm可以获取list的几个相关库,但是我们这里注重于自己动手实现,接下来就一起来看一下Node.js环境下JavaScript实现单链表与双链表结构
单链表（LinkedList）的javascript实现
npmjs相关库：
complex-list、smart-list、singly-linked-list
编程思路：
- add方法用于将元素追加到链表尾部，借由insert方法来实现；
- 注意各个函数的边界条件处理。
自己的实现：
SingleNode.js
(function(){
"use strict";
function Node(element){
this.element = element;
this.next = null;
}
module.exports = Node;
})();
LinkedList.js
(function(){
"use strict";
var Node = require("./lib/SingleNode");
function LinkedList(){
this._head = new Node("This is Head Node.");
this._size = 0;
}
LinkedList.prototype.isEmpty = function(){
return this._size === 0;
};
LinkedList.prototype.size = function(){
return this._size;
};
LinkedList.prototype.getHead = function(){
return this._head;
};
LinkedList.prototype.display = function(){
var currNode = this.getHead().next;
while(currNode){
console.log(currNode.element);
currNode = currNode.next;
}
};
LinkedList.prototype.remove = function(item){
if(item) {
var preNode = this.findPre(item);
if(preNode == null)
return ;
if (preNode.next !== null) {
preNode.next = preNode.next.next;
this._size--;
}
}
};
LinkedList.prototype.add = function(item){
this.insert(item);
};
LinkedList.prototype.insert = function(newElement, item){
var newNode = new Node(newElement);
var finder = item ? this.find(item) : null;
if(!finder){
var last = this.findLast();
last.next = newNode;
}
else{
newNode.next = finder.next;
finder.next = newNode;
}
this._size++;
};
/*********************** Utility Functions ********************************/
LinkedList.prototype.findLast = function(){
var currNode = this.getHead();
while(currNode.next){
currNode = currNode.next;
}
return currNode;
};
LinkedList.prototype.findPre = function(item){
var currNode = this.getHead();
while(currNode.next !== null && currNode.next.element !== item){
currNode = currNode.next;
}
return currNode;
};
LinkedList.prototype.find = function(item){
if(item == null)
return null;
var currNode = this.getHead();
while(currNode && currNode.element !== item){
currNode = currNode.next;
}
return currNode;
};
module.exports = LinkedList;
})();
双链表（DoubleLinkedList）的javascript实现
npmjs相关库：
complex-list、smart-list
编程思路：
- 双链表多了一个指向前趋的指针，故单链表中的辅助函数findPre就不需要了；
- 增加了反向输出方法；
- 注意边界条件的处理。
自己的实现
DoubleNode.js
(function(){
"use strict";
function Node(element){
this.element = element;
this.next = null;
this.previous = null;
}
module.exports = Node;
})();
DoubleLinkedList.js
(function(){
"use strict";
var Node = require("./lib/DoubleNode");
function DoubleLinkedList(){
this._head = new Node("This is Head Node.");
this._size = 0;
}
DoubleLinkedList.prototype.getHead = function(){
return this._head;
};
DoubleLinkedList.prototype.isEmpty = function(){
return this._size === 0;
};
DoubleLinkedList.prototype.size = function(){
return this._size;
};
DoubleLinkedList.prototype.findLast = function(){
var currNode = this.getHead();
while(currNode.next){
currNode = currNode.next;
}
return currNode;
};
DoubleLinkedList.prototype.add = function(item){
if(item == null)
return null;
this.insert(item);
};
DoubleLinkedList.prototype.remove = function(item){
if(item) {
var node = this.find(item);
if(node == null)
return ;
if (node.next === null) {
node.previous.next = null;
node.previous = null;
} else{
node.previous.next = node.next;
node.next.previous = node.previous;
node.next = null;
node.previous = null;
}
this._size--;
}
};
DoubleLinkedList.prototype.find = function(item){
if(item == null)
return null;
var currNode = this.getHead();
while(currNode && currNode.element !== item){
currNode = currNode.next;
}
return currNode;
};
DoubleLinkedList.prototype.insert = function(newElement, item){
var newNode = new Node(newElement);
var finder = item ? this.find(item) : null;
if(!finder){
var last = this.findLast();
newNode.previous = last;
last.next = newNode;
}
else{
newNode.next = finder.next;
newNode.previous = finder;
finder.next.previous = newNode;
finder.next = newNode;
}
this._size++;
};
DoubleLinkedList.prototype.dispReverse = function(){
var currNode = this.findLast();
while(currNode != this.getHead()){
console.log(currNode.element);
currNode = currNode.previous;
}
};
DoubleLinkedList.prototype.display = function(){
var currNode = this.getHead().next;
while(currNode){
console.log(currNode.element);
currNode = currNode.next;
}
};
module.exports = DoubleLinkedList;
})();