FazBrowse GitHub Viewer
|
Trending
|
URL:
|
Home
Tools:
[Download Repo ZIP]
[View Raw Code]
[Original HTTPS Page]
Java/Others/QueueUsingTwoStacks.java at master · primary-code-test/Java · GitHub
primary-code-test
Java
Repository navigation
Code
Pull requests
Actions
Projects
Security and quality
Insights
Expand file tree
Breadcrumbs
Java
/
Others
/
QueueUsingTwoStacks.java
Copy path
More file actions
More file actions
Latest commit
History
History
History
150 lines (134 loc) · 3.82 KB
Breadcrumbs
Java
/
Others
/
QueueUsingTwoStacks.java
Copy path
File metadata and controls
150 lines (134 loc) · 3.82 KB
Raw
Copy raw file
Download raw file
Open symbols panel
Edit and raw actions
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
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
package
Others
;
import
java
.
util
.
Stack
;
/**
* This implements Queue using two Stacks.
*
* <p>Big O Runtime: insert(): O(1) remove(): O(1) amortized isEmpty(): O(1)
*
* <p>A queue data structure functions the same as a real world queue. The elements that are added
* first are the first to be removed. New elements are added to the back/rear of the queue.
*
* @author sahilb2 (https://www.github.com/sahilb2)
*/
class
QueueWithStack
{
// Stack to keep track of elements inserted into the queue
private
Stack
inStack
;
// Stack to keep track of elements to be removed next in queue
private
Stack
outStack
;
/** Constructor */
public
QueueWithStack
() {
this
.
inStack
=
new
Stack
();
this
.
outStack
=
new
Stack
();
}
/**
* Inserts an element at the rear of the queue
*
* @param x element to be added
*/
public
void
insert
(
Object
x
) {
// Insert element into inStack
this
.
inStack
.
push
(
x
);
}
/**
* Remove an element from the front of the queue
*
* @return the new front of the queue
*/
public
Object
remove
() {
if
(
this
.
outStack
.
isEmpty
()) {
// Move all elements from inStack to outStack (preserving the order)
while
(!
this
.
inStack
.
isEmpty
()) {
this
.
outStack
.
push
(
this
.
inStack
.
pop
());
}
}
return
this
.
outStack
.
pop
();
}
/**
* Peek at the element from the front of the queue
*
* @return the front element of the queue
*/
public
Object
peekFront
() {
if
(
this
.
outStack
.
isEmpty
()) {
// Move all elements from inStack to outStack (preserving the order)
while
(!
this
.
inStack
.
isEmpty
()) {
this
.
outStack
.
push
(
this
.
inStack
.
pop
());
}
}
return
this
.
outStack
.
peek
();
}
/**
* Peek at the element from the back of the queue
*
* @return the back element of the queue
*/
public
Object
peekBack
() {
return
this
.
inStack
.
peek
();
}
/**
* Returns true if the queue is empty
*
* @return true if the queue is empty
*/
public
boolean
isEmpty
() {
return
(
this
.
inStack
.
isEmpty
() &&
this
.
outStack
.
isEmpty
());
}
}
/**
* This class is the example for the Queue class
*
* @author sahilb2 (https://www.github.com/sahilb2)
*/
public
class
QueueUsingTwoStacks
{
/**
* Main method
*
* @param args Command line arguments
*/
public
static
void
main
(
String
args
[]) {
QueueWithStack
myQueue
=
new
QueueWithStack
();
myQueue
.
insert
(
1
);
System
.
out
.
println
(
myQueue
.
peekBack
());
// Will print 1
// instack: [(top) 1]
// outStack: []
myQueue
.
insert
(
2
);
System
.
out
.
println
(
myQueue
.
peekBack
());
// Will print 2
// instack: [(top) 2, 1]
// outStack: []
myQueue
.
insert
(
3
);
System
.
out
.
println
(
myQueue
.
peekBack
());
// Will print 3
// instack: [(top) 3, 2, 1]
// outStack: []
myQueue
.
insert
(
4
);
System
.
out
.
println
(
myQueue
.
peekBack
());
// Will print 4
// instack: [(top) 4, 3, 2, 1]
// outStack: []
System
.
out
.
println
(
myQueue
.
isEmpty
());
// Will print false
System
.
out
.
println
(
myQueue
.
remove
());
// Will print 1
System
.
out
.
println
(
myQueue
.
peekBack
());
// Will print NULL
// instack: []
// outStack: [(top) 2, 3, 4]
myQueue
.
insert
(
5
);
System
.
out
.
println
(
myQueue
.
peekFront
());
// Will print 2
// instack: [(top) 5]
// outStack: [(top) 2, 3, 4]
myQueue
.
remove
();
System
.
out
.
println
(
myQueue
.
peekFront
());
// Will print 3
// instack: [(top) 5]
// outStack: [(top) 3, 4]
myQueue
.
remove
();
System
.
out
.
println
(
myQueue
.
peekFront
());
// Will print 4
// instack: [(top) 5]
// outStack: [(top) 4]
myQueue
.
remove
();
// instack: [(top) 5]
// outStack: []
System
.
out
.
println
(
myQueue
.
peekFront
());
// Will print 5
// instack: []
// outStack: [(top) 5]
myQueue
.
remove
();
// instack: []
// outStack: []
System
.
out
.
println
(
myQueue
.
isEmpty
());
// Will print true
}
}
Back
|
FazBrowse Home
|
New Git URL