/
MyLinkedList.java
117 lines (106 loc) · 2.53 KB
/
MyLinkedList.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
package g0701_0800.s0707_design_linked_list;
// #Medium #Design #Linked_List #Data_Structure_II_Day_12_Linked_List #Programming_Skills_II_Day_19
// #Udemy_Linked_List #2022_03_23_Time_10_ms_(70.60%)_Space_50.6_MB_(48.08%)
public class MyLinkedList {
private static class Node {
int val;
Node next;
Node(int val) {
this.val = val;
this.next = null;
}
}
private Node head;
private Node tail;
private int size;
public MyLinkedList() {
this.head = this.tail = null;
this.size = 0;
}
public int get(int index) {
if (index >= size) {
return -1;
}
if (index == 0) {
return head.val;
}
int i = 0;
Node ptr = head;
while (i++ < index - 1) {
ptr = ptr.next;
}
return ptr.next.val;
}
public void addAtHead(int val) {
Node node = new Node(val);
if (head == null) {
head = tail = node;
size++;
return;
}
node.next = head;
head = node;
size++;
}
public void addAtTail(int val) {
if (head == null) {
addAtHead(val);
return;
}
Node node = new Node(val);
tail.next = node;
tail = node;
size++;
}
public void addAtIndex(int index, int val) {
if (index > size) {
return;
}
if (index == 0) {
addAtHead(val);
return;
}
if (index == size) {
addAtTail(val);
return;
}
int i = 0;
Node node = new Node(val);
Node ptr = head;
while (i++ < index - 1) {
ptr = ptr.next;
}
node.next = ptr.next;
ptr.next = node;
size++;
}
public void deleteAtIndex(int index) {
if (index >= size) {
return;
}
if (index == 0) {
head = head.next;
size--;
return;
}
int i = 0;
Node ptr = head;
while (i++ < index - 1) {
ptr = ptr.next;
}
ptr.next = ptr.next.next;
if (index == size - 1) {
tail = ptr;
}
size--;
}
}
/*
* Your MyLinkedList object will be instantiated and called as such:
* MyLinkedList obj = new MyLinkedList();
* int param_1 = obj.get(index);
* obj.addAtHead(val);
* obj.addAtTail(val);
* obj.addAtIndex(index,val);
* obj.deleteAtIndex(index);
*/