11package com .coding .basic ;
22
3+ import com .coding .basic .LinkedList .Node ;
4+
35public class LinkedList implements List {
46
57 private Node head ;
8+ private int size ;
69
710 public void add (Object o ){
8-
11+ if (head .data == null ) {
12+ head .data = o ;
13+ head .next = null ;
14+ size ++;
15+ return ;
16+ }
17+ Node node = new Node (o );
18+ Node curr = head ;
19+ while (curr .next != null ) {
20+ curr = curr .next ;
21+ }
22+ curr .next = node ;
23+ size ++;
924 }
1025 public void add (int index , Object o ){
11-
26+ if (index < 0 || index > size ) {
27+ System .out .println (index + "无效指数" );
28+ return ;
29+ }
30+ if (head .data == null ) {
31+ if (index == 0 ) {
32+ head .data = o ;
33+ head .next = null ;
34+ size ++;
35+ return ;
36+ } else {
37+ System .out .println ("无效指数" );
38+ return ;
39+ }
40+ }
41+ Node node = new Node (o );
42+ Node curr = head ;
43+ for (int i = 0 ; i < index - 1 ; i ++) {
44+ curr = curr .next ;
45+ }
46+ Node temp = curr .next ;
47+ curr .next = node ;
48+ node .next = temp ;
49+ size ++;
1250 }
1351 public Object get (int index ){
14- return null ;
52+ if (index < 0 || index > size ) {
53+ System .out .println (index + " is invalid index!" );
54+ return null ;
55+ }
56+ Node result = head ;
57+ for (int i = 0 ; i < index ; i ++) {
58+ result = result .next ;
59+ }
60+ return result ;
1561 }
1662 public Object remove (int index ){
17- return null ;
63+ if (index < 0 || index > size ) {
64+ System .out .println (index + " is invalid index!" );
65+ return null ;
66+ }
67+ Node curr = head ;
68+ for (int i = 0 ; i < index - 1 ; i ++) {
69+ curr = curr .next ;
70+ }
71+ Node result = curr .next ;
72+ curr .next = curr .next .next ;
73+ size --;
74+ return result ;
1875 }
1976
2077 public int size (){
21- return - 1 ;
78+ return this . size ;
2279 }
2380
2481 public void addFirst (Object o ){
25-
82+ if (head .data == null ) {
83+ head .data = o ;
84+ head .next = null ;
85+ size ++;
86+ return ;
87+ }
88+ Node temp = head ;
89+ head = new Node (o );
90+ head .next = temp ;
91+ size ++;
2692 }
2793 public void addLast (Object o ){
28-
94+ if (head .data == null ) {
95+ head .data = o ;
96+ head .next = null ;
97+ size ++;
98+ return ;
99+ }
100+ Node node = new Node (o );
101+ Node curr = head ;
102+ while (curr .next != null ) {
103+ curr = curr .next ;
104+ }
105+ curr .next = node ;
106+ size ++;
29107 }
30108 public Object removeFirst (){
31- return null ;
109+ if (head .data == null ) {
110+ return null ;
111+ }
112+ Node result = head ;
113+ head = head .next ;
114+ size --;
115+ return result ;
32116 }
33117 public Object removeLast (){
34- return null ;
118+ if (head .data == null ) {
119+ return null ;
120+ }
121+ Node curr = head ;
122+ for (int i = 0 ; i < size - 1 ; i ++) {
123+ curr = curr .next ;
124+ }
125+ Node result = curr .next ;
126+ curr .next = null ;
127+ size --;
128+ return result ;
35129 }
36130 public Iterator iterator (){
37131 return null ;
@@ -41,6 +135,12 @@ public Iterator iterator(){
41135 private static class Node {
42136 Object data ;
43137 Node next ;
138+ public Node (Object o ) {
139+ data = o ;
140+ next = null ;
141+ }
142+
143+
44144
45145 }
46146}
0 commit comments