Converting Reverse Polish to Infix Notation in Java
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2
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I am trying to solve a programming challange that involves converting reverse polish notation to infix notation. For example: 1 3 + 2 4 5 - + / would be: ((1+3)/(2+(4-5))) My solution so far does work, but it's not fast enough. So I am looking for any optimization advice.
public class betteralgo {
public static void main(String args) throws IOException {
BufferedReader bi = new BufferedReader(new
InputStreamReader(System.in));
String line = bi.readLine();
String input = line.split(" ");
StringBuilder builder = new StringBuilder();
Stack<String> stack = new Stack<String>();
for(String e:input) {
switch(e){
case("+"):
case("-"):
case("*"):
case("/"):
String i = stack.pop();
String k = stack.pop();
stack.push("(" + k + e + i + ")");
break;
default:
stack.push(e);
}
}
System.out.println(stack.pop());
}
}
java performance algorithm math-expression-eval
edited Sep 7 at 14:51
200_success
128k15149412
asked Sep 7 at 12:12
Joakim Hauger
112
bumped to the homepage by Community♦ 1 hour ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
add a comment |
up vote
2
down vote
favorite
I am trying to solve a programming challange that involves converting reverse polish notation to infix notation. For example: 1 3 + 2 4 5 - + / would be: ((1+3)/(2+(4-5))) My solution so far does work, but it's not fast enough. So I am looking for any optimization advice.
public class betteralgo {
public static void main(String args) throws IOException {
BufferedReader bi = new BufferedReader(new
InputStreamReader(System.in));
String line = bi.readLine();
String input = line.split(" ");
StringBuilder builder = new StringBuilder();
Stack<String> stack = new Stack<String>();
for(String e:input) {
switch(e){
case("+"):
case("-"):
case("*"):
case("/"):
String i = stack.pop();
String k = stack.pop();
stack.push("(" + k + e + i + ")");
break;
default:
stack.push(e);
}
}
System.out.println(stack.pop());
}
}
java performance algorithm math-expression-eval
edited Sep 7 at 14:51
200_success
128k15149412
asked Sep 7 at 12:12
Joakim Hauger
112
bumped to the homepage by Community♦ 1 hour ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
3
"it's not fast enough" – for which input? How long does it take? Is there a concrete time limit that you need to achieve?
– Martin R
Sep 7 at 12:52
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I am trying to solve a programming challange that involves converting reverse polish notation to infix notation. For example: 1 3 + 2 4 5 - + / would be: ((1+3)/(2+(4-5))) My solution so far does work, but it's not fast enough. So I am looking for any optimization advice.
public class betteralgo {
public static void main(String args) throws IOException {
BufferedReader bi = new BufferedReader(new
InputStreamReader(System.in));
String line = bi.readLine();
String input = line.split(" ");
StringBuilder builder = new StringBuilder();
Stack<String> stack = new Stack<String>();
for(String e:input) {
switch(e){
case("+"):
case("-"):
case("*"):
case("/"):
String i = stack.pop();
String k = stack.pop();
stack.push("(" + k + e + i + ")");
break;
default:
stack.push(e);
}
}
System.out.println(stack.pop());
}
}
java performance algorithm math-expression-eval
edited Sep 7 at 14:51
200_success
128k15149412
asked Sep 7 at 12:12
Joakim Hauger
112
I am trying to solve a programming challange that involves converting reverse polish notation to infix notation. For example: 1 3 + 2 4 5 - + / would be: ((1+3)/(2+(4-5))) My solution so far does work, but it's not fast enough. So I am looking for any optimization advice.
public class betteralgo {
public static void main(String args) throws IOException {
BufferedReader bi = new BufferedReader(new
InputStreamReader(System.in));
String line = bi.readLine();
String input = line.split(" ");
StringBuilder builder = new StringBuilder();
Stack<String> stack = new Stack<String>();
for(String e:input) {
switch(e){
case("+"):
case("-"):
case("*"):
case("/"):
String i = stack.pop();
String k = stack.pop();
stack.push("(" + k + e + i + ")");
break;
default:
stack.push(e);
}
}
System.out.println(stack.pop());
}
}
java performance algorithm math-expression-eval
java performance algorithm math-expression-eval
edited Sep 7 at 14:51
200_success
128k15149412
asked Sep 7 at 12:12
Joakim Hauger
112
edited Sep 7 at 14:51
200_success
128k15149412
asked Sep 7 at 12:12
Joakim Hauger
112
edited Sep 7 at 14:51
200_success
128k15149412
edited Sep 7 at 14:51
200_success
128k15149412
edited Sep 7 at 14:51
200_success
128k15149412
128k15149412
asked Sep 7 at 12:12
Joakim Hauger
112
asked Sep 7 at 12:12
Joakim Hauger
112
asked Sep 7 at 12:12
Joakim Hauger
112
112
bumped to the homepage by Community♦ 1 hour ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
bumped to the homepage by Community♦ 1 hour ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
3
"it's not fast enough" – for which input? How long does it take? Is there a concrete time limit that you need to achieve?
– Martin R
Sep 7 at 12:52
add a comment |
3
"it's not fast enough" – for which input? How long does it take? Is there a concrete time limit that you need to achieve?
– Martin R
Sep 7 at 12:52
3
3
"it's not fast enough" – for which input? How long does it take? Is there a concrete time limit that you need to achieve?
– Martin R
Sep 7 at 12:52
"it's not fast enough" – for which input? How long does it take? Is there a concrete time limit that you need to achieve?
– Martin R
Sep 7 at 12:52
add a comment |
1 Answer
1
active
oldest
votes
up vote
0
down vote
If you want to do it faster I know that I once solved this with a hashMap which is much faster. The problem is that, depending on what you are going to use it for, it's harder to implement. I don't have time to show exactly how I did it now, I might come back to you, but it should give you a pointer on where to look.
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
answered Sep 17 at 16:33
NaCl-e
1
add a comment |
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active
oldest
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up vote
0
down vote
If you want to do it faster I know that I once solved this with a hashMap which is much faster. The problem is that, depending on what you are going to use it for, it's harder to implement. I don't have time to show exactly how I did it now, I might come back to you, but it should give you a pointer on where to look.
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
answered Sep 17 at 16:33
NaCl-e
1
add a comment |
up vote
0
down vote
If you want to do it faster I know that I once solved this with a hashMap which is much faster. The problem is that, depending on what you are going to use it for, it's harder to implement. I don't have time to show exactly how I did it now, I might come back to you, but it should give you a pointer on where to look.
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
answered Sep 17 at 16:33
NaCl-e
1
add a comment |
up vote
0
down vote
up vote
0
down vote
If you want to do it faster I know that I once solved this with a hashMap which is much faster. The problem is that, depending on what you are going to use it for, it's harder to implement. I don't have time to show exactly how I did it now, I might come back to you, but it should give you a pointer on where to look.
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
answered Sep 17 at 16:33
NaCl-e
1
If you want to do it faster I know that I once solved this with a hashMap which is much faster. The problem is that, depending on what you are going to use it for, it's harder to implement. I don't have time to show exactly how I did it now, I might come back to you, but it should give you a pointer on where to look.
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
answered Sep 17 at 16:33
NaCl-e
1
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
edited Sep 17 at 16:52
Sᴀᴍ Onᴇᴌᴀ
8,13861752
8,13861752
answered Sep 17 at 16:33
NaCl-e
1
answered Sep 17 at 16:33
NaCl-e
1
answered Sep 17 at 16:33
NaCl-e
1
1
add a comment |
add a comment |
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3
"it's not fast enough" – for which input? How long does it take? Is there a concrete time limit that you need to achieve?
– Martin R
Sep 7 at 12:52