這段時間惡補了數據結構。雖然工作中用處不大，但是這是計算機基礎。畢竟，掌握原理，才能獲得真正的自由
數據結構彙總
這次學習了以下數據結構，並使用JavaScript對其一一封裝
- 棧
- 隊列
- 鏈表
棧和隊列
首先棧和隊列都是線性儲存數據的一種方式，要理解它們都是存儲數據的，再者是線性存儲的。
兩者有什麼不同？
棧的儲存數據規則是先進後出
隊列的儲存數據規則是先進先出
注意：怎麼進怎麼出，只是在數據存儲時的一種規則，這樣符合此規則的場景下使用該數據類型會顯得更高效。
因為JavaScript沒有對應的數據類型，所以如果我們要使用，需要自己封裝，我們基於數組來簡單的封裝下：
棧
<code>class
Z
{constructor
() {this
.items = []; } /<code>
隊列
<code>class
D
{constructor
() {this
.items = []; } push(item) {this
.items.push(item); } pop() {this
.items.shift(); } isEmpty() {return
this
.items.length ===0
; } len() {return
this
.items.length; } }/<code>
鏈表
什麼是鏈表？
鏈表是一種將數據存儲到“結點”中的數據結構，需要存儲多少個數據，就生成多少個“結點”，把這些“結點”用指針掛接起來
鏈表的分類
常見的鏈表有單項列表和雙向鏈表兩種
單項鍊表
每個結點有兩部分組成，分別是next(指向下一個結點的data)和自身的data，如圖所示：
雙向鏈表每個結點有三部分組成，分別是next(指向下一個結點的data)prev(指向上一個結點的data)及自身結點的data。如圖所示：
其中：head結點指針指向第一個結點，tail指針指向最後一個結點
單項鍊表封裝
<code>function linkedList() {
function Node(data
) {
this
.data
= data
;
this
.next = null
;
}
this
.head = null
;
this
.length = 0
;
linkedList.prototype.append = function(data
) {
var
newNode = new Node(data
);
if
(this
.length == 0
) {
this
.head = newNode
} else
{
var
current = this
.head;
while
(current.next) {
current = current.next;
}
current.next = newNode;
}
this
.length++;
}
linkedList.prototype.insert = function(position, data
) {
if
(position 0
|| position > this
.length) {
return
false
;
}
var
newNode = new Node(data
);
if
(position == 0
) {
newNode.next = this
.head;
this
.head = newNode;
} else
{
var
index = 0
;
var
current = this
.head;
var
previous = null
;
while
(index++ < position) {
previous = current;
current = current.next;
}
newNode.next = current;
previous.next = newNode;
}
this
.length++;
return
true
;
}
linkedList.prototype.get
= function(position) {
if
(position 0
|| position >= this
.length) {
return
null
;
}
var
current = this
.head;
var
index = 0
;
while
(index++ < position) {
current = current.next;
}
return
current.next;
}
linkedList.prototype.indexOf = function(data
) {
var
current = this
.head;
var
index = 0
;
while
(current) {
if
(current.data
== data
) {
return
index;
}
current = current.next;
index++;
}
return
- 1
;
}
linkedList.prototype.updata = function(position, data
) {
if
(position 0
|| position >= this
.length) {
return
false
;
}
var
current = this
.head;
var
index = 0
;
while
(index++ < position) {
current = current.next;
}
current.data
= data
;
return
true
;
}
linkedList.prototype.removeAt = function(position) {
if
(position 0
|| position >= this
.length) {
return
false
;
}
if
(position == 0
) {
this
.head = this
.head.next;
} else
{
var
current = this
.head;
var
previous = null
;
var
index = 0
;
while
(index++ < position) {
position = current;
current = current.next;
}
previous.next = current.next;
}
this
.length -= 1
;
return
true
;
}
linkedList.prototype.toString = function() {
var
current = this
.head;
var
listString = ''
;
while
(current) {
listString += current.data
+ ' '
current = current.next;
}
return
listString;
}
}/<code>雙向鏈表封裝
<code>function DoublyList(){
this
.head = null
;
this
.tail = null
;
this
.length = 0
;
function Node(data
){
this
.data
= data
;
this
.prev = null
;
this
.next = null
;
}
DoublyList.prototype.append = function(data
){
var
newNode = new Node(data
);
if
(this
.length == 0
){
this
.head = newNode;
this
.tail = newNode;
}else
{
newNode.prev = this
.tail;
this
.tail.next = newNode;
this
.tail = newNode;
}
this
.length +=1
;
}
DoublyList.prototype.insert = function(position,data
){
if
(position<0
|| position>this
.length) return
false
;
var
newNode = new Node(data
);
if
(this
.length == 0
){
this
.head = newNode;
this
.tail = newNode;
}
if
(position == 0
){
this
.head.prev = newNode;
newNode.next = this
.head;
this
.head = newNode;
}else
if
(position == this
.length){
newNode.prev = this
.tail;
this
.tail.next = newNode;
this
.tail = newNode;
}else
{
var
current = this
.head;
var
index = 0
;
while
(index++ /<code>
