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链表用来存储有序元素的集合。
function LinkedList() {
let Node = function(element){
this.element = element;
this.next = null;
};
let length = 0;
let head = null;
this.append = function(element){
let node = new Node(element),
current;
if (head === null){ //first node on list
head = node;
} else {
current = head;
//loop the list until find last item
while(current.next){
current = current.next;
}
//get last item and assign next to added item to make the link
current.next = node;
}
length++; //update size of list
};
this.insert = function(position, element){
//check for out-of-bounds values
if (position >= 0 && position <= length){
let node = new Node(element),
current = head,
previous,
index = 0;
if (position === 0){ //add on first position
node.next = current;
head = node;
} else {
while (index++ < position){
previous = current;
current = current.next;
}
node.next = current;
previous.next = node;
}
length++; //update size of list
return true;
} else {
return false;
}
};
this.removeAt = function(position){
//check for out-of-bounds values
if (position > -1 && position < length){
let current = head,
previous,
index = 0;
//removing first item
if (position === 0){
head = current.next;
} else {
while (index++ < position){
previous = current;
current = current.next;
}
//link previous with current's next - skip it to remove
previous.next = current.next;
}
length--;
return current.element;
} else {
return null;
}
};
this.remove = function(element){
let index = this.indexOf(element);
return this.removeAt(index);
};
this.indexOf = function(element){
let current = head,
index = 0;
while (current) {
if (element === current.element) {
return index;
}
index++;
current = current.next;
}
return -1;
};
this.isEmpty = function() {
return length === 0;
};
this.size = function() {
return length;
};
this.getHead = function(){
return head;
};
this.toString = function(){
let current = head,
string = '';
while (current) {
string += current.element + (current.next ? ', ' : '');
current = current.next;
}
return string;
};
this.print = function(){
console.log(this.toString());
};
}链表es6闭包的形式。
let LinkedList2 = (function () {
class Node {
constructor(element){
this.element = element;
this.next = null;
}
}
const length = new WeakMap();
const head = new WeakMap();
class LinkedList2 {
constructor () {
length.set(this, 0);
head.set(this, null);
}
append(element) {
let node = new Node(element),
current;
if (this.getHead() === null) { //first node on list
head.set(this, node);
} else {
current = this.getHead();
//loop the list until find last item
while (current.next) {
current = current.next;
}
//get last item and assign next to added item to make the link
current.next = node;
}
//update size of list
let l = this.size();
l++;
length.set(this, l);
}
insert(position, element) {
//check for out-of-bounds values
if (position >= 0 && position <= this.size()) {
let node = new Node(element),
current = this.getHead(),
previous,
index = 0;
if (position === 0) { //add on first position
node.next = current;
head.set(this, node);
} else {
while (index++ < position) {
previous = current;
current = current.next;
}
node.next = current;
previous.next = node;
}
//update size of list
let l = this.size();
l++;
length.set(this, l);
return true;
} else {
return false;
}
}
removeAt(position) {
//check for out-of-bounds values
if (position > -1 && position < this.size()) {
let current = this.getHead(),
previous,
index = 0;
//removing first item
if (position === 0) {
head.set(this, current.next);
} else {
while (index++ < position) {
previous = current;
current = current.next;
}
//link previous with current's next - skip it to remove
previous.next = current.next;
}
let l = this.size();
l--;
length.set(this, l);
return current.element;
} else {
return null;
}
}
remove(element) {
let index = this.indexOf(element);
return this.removeAt(index);
}
indexOf(element) {
let current = this.getHead(),
index = 0;
while (current) {
if (element === current.element) {
return index;
}
index++;
current = current.next;
}
return -1;
}
isEmpty() {
return this.size() === 0;
}
size() {
return length.get(this);
}
getHead() {
return head.get(this);
}
toString() {
let current = this.getHead(),
string = '';
while (current) {
string += current.element + (current.next ? ', ' : '');
current = current.next;
}
return string;
}
print() {
console.log(this.toString());
}
}
return LinkedList2;
})();