forked from guokaide/algorithm
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathListQueue.java
More file actions
79 lines (65 loc) · 1.61 KB
/
ListQueue.java
File metadata and controls
79 lines (65 loc) · 1.61 KB
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
package queue;
public class ListQueue<T> implements Queue<T> {
Node head = null;
Node tail = null;
// T(N)=O(1)
@Override
public boolean enqueue(T item) {
Node newNode = new Node(item, null);
if (tail == null) {
tail = newNode;
head = newNode;
return true;
}
tail.next = newNode;
tail = tail.next;
return true;
}
// T(N)=O(1)
@Override
public T dequeue() {
if (head == null) {
return null;
}
Node tmp = head;
head = head.next;
tmp.next = null;
return (T) tmp.getData();
}
// for test
public void printAll() {
System.out.print("[");
for (Node p = head; p != null; p = p.next) {
System.out.print(p.getData() + " ");
}
System.out.print("]");
System.out.println();
}
private static class Node<T>{
private T data;
private Node next;
public Node(T data, Node next) {
this.data = data;
this.next = next;
}
public T getData() {
return this.data;
}
}
public static void main(String[] args) {
ListQueue<String> queue = new ListQueue<>();
queue.printAll();
queue.enqueue("A");
queue.printAll();
queue.enqueue("B");
queue.enqueue("C");
queue.enqueue("D");
queue.printAll();
queue.enqueue("E");
queue.printAll();
queue.dequeue();
queue.dequeue();
queue.dequeue();
queue.printAll();
}
}