1+ <!DOCTYPE html>
2+ < html >
3+ < head >
4+ < meta charset ="utf-8 ">
5+ < title > LinkedList</ title >
6+ < script type ="text/javascript ">
7+ function LinkedList ( ) {
8+ //Node类表示链表中操作的项
9+ var Node = function ( element ) {
10+ this . element = element ;
11+ this . next = null ;
12+ }
13+
14+ var length = 0 ;
15+ var head = null ;
16+
17+ //链表尾部添加一项
18+ this . append = function ( element ) {
19+ var node = new Node ( element ) ;
20+ var current ;
21+ if ( head == null ) {
22+ head = node ;
23+ } else {
24+ current = head ;
25+ while ( current . next ) {
26+ current = current . next ;
27+ }
28+ current . next = node ;
29+ }
30+ length ++ ;
31+ } ;
32+
33+ //特定位置添加元素
34+ this . insert = function ( position , element ) {
35+ var node = new Node ( element ) ;
36+ var current = head ;
37+ var previous ;
38+ var index = 0 ;
39+
40+ //检查越界位置
41+ if ( position >= 0 && position <= length ) {
42+ if ( position === 0 ) {
43+ node . next = current ;
44+ head = node ;
45+ } else {
46+ while ( index ++ < position ) {
47+ previous = current ;
48+ current = current . next ;
49+ }
50+ node . next = current ;
51+ previous . next = node ;
52+ }
53+ length ++ ;
54+ return true ;
55+ } else {
56+ return false ;
57+ }
58+ } ;
59+
60+ //从链表中移除特定位置一项
61+ this . removeAt = function ( position ) {
62+
63+ if ( position > - 1 && position < length ) { //下标越界检查
64+ var current = head ;
65+ var previous ;
66+ var index = 0 ;
67+
68+ if ( position === 0 ) {
69+ head = current . next ;
70+ } else {
71+ while ( index ++ < position ) {
72+ previous = current ;
73+ current = current . next ;
74+ }
75+ previous . next = current . next ;
76+ }
77+ length -- ;
78+ return current . element ;
79+ } else {
80+ return null ;
81+ }
82+ } ;
83+
84+ //从链表中移除一项
85+ this . remove = function ( element ) {
86+ var index = this . indexOf ( element ) ;
87+ return this . removeAt ( index ) ;
88+ } ;
89+
90+ //返回列表中项的索引
91+ this . indexOf = function ( element ) {
92+ var current = head ;
93+ var index = 0 ;
94+ while ( current ) {
95+ if ( element == current . element ) {
96+ return index ;
97+ }
98+ index ++ ;
99+ current = current . next ;
100+ }
101+ return - 1 ;
102+ } ;
103+ //判空
104+ this . isEmpty = function ( ) {
105+ return length === 0 ;
106+ } ;
107+ //链表中的长度
108+ this . size = function ( ) {
109+ return length ;
110+ } ;
111+
112+ //返回第一个元素
113+ this . getHead = function ( ) {
114+ return head ;
115+ }
116+
117+ this . toString = function ( ) {
118+ var current = head ;
119+ var string = '' ;
120+ while ( current ) {
121+ string += current . element ;
122+ current = current . next ;
123+ }
124+ return string ;
125+ } ;
126+
127+ this . print = function ( ) {
128+ console . log ( this . toString ( ) ) ;
129+ }
130+ }
131+
132+ //双向链表
133+ function DoublyLinkedList ( ) {
134+ //操作的数据结构
135+ function Node ( element ) {
136+ this . element = element ;
137+ this . prev = null ;
138+ this . next = null ;
139+ }
140+
141+ var length = 0 ;
142+ var head = null ;
143+ var tail = null ;
144+
145+ //在任意位置插入元素
146+ this . insert = function ( position , element ) {
147+
148+ if ( position >= 0 && position <= length ) {
149+ var node = new Node ( element ) ;
150+ var current = head ;
151+ var previous ;
152+ var index = 0 ;
153+
154+ if ( position === 0 ) {
155+ if ( ! head ) {
156+ head = node ;
157+ tail = node ;
158+ } else {
159+ node . next = current ;
160+ current . prev = node ;
161+ head = node ;
162+ }
163+ } else if ( position === length ) {
164+ current = tail ;
165+ current . next = node ;
166+ node . prev = current ;
167+ tail = node ;
168+ } else {
169+ while ( index ++ < position ) {
170+ previous = current ;
171+ current = current . next ;
172+ }
173+ node . next = current ;
174+ previous . next = node ;
175+
176+ current . prev = node ;
177+ node . prev = previous ;
178+ }
179+
180+ length ++ ; //更新链表长度
181+
182+ return true ;
183+ } else {
184+ return false ;
185+ }
186+ } ;
187+
188+ this . removeAt ( position ) {
189+
190+ if ( position > - 1 && position < length ) {
191+
192+ var current = head ;
193+ var previous ;
194+ var index = 0 ;
195+
196+ //移除第一项
197+ if ( position === 0 ) {
198+ head = current . next ;
199+
200+ //如果只有一项，更新tail
201+ if ( length === 1 ) {
202+ tail = null ;
203+ } else {
204+ head . prev = null ;
205+ }
206+ } else if ( position === length - 1 ) {
207+ current = tail ;
208+ tail = current . prev ;
209+ tail . next = null ;
210+ } else {
211+
212+ while ( index ++ < position ) {
213+ previous = current ;
214+ current = current . next ;
215+ }
216+
217+ previous . next = current . next ;
218+ current . next . prev = previous ;
219+ }
220+ length -- ;
221+ return current . element ;
222+ } else {
223+ return null ;
224+ }
225+ }
226+ }
227+ </ script >
228+ </ head >
229+ < body >
230+
231+ </ body >
232+ </ html >
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