Problem with Generate Parenthesis Problem
I have been trying to program the Generate Parenthesis problem on Leetcode, but I keep on getting "Memory Limit Exceeds", which means that I have an infinite loop in my code. However, I cannot understand why there will be infinite loop/recursion. Thank you!
class Solution {
public List<String> generateParenthesis(int n) {
List<String> permutations = new ArrayList<String>();
permute(permutations, "" , n, n);
return permutations;
}
public void permute (List<String> permutations, String paren, int left, int right){
if(left == 0 && right == 0){
permutations.add(paren);
return;
}
if(left > 0){
permute(permutations, paren + "(", left--, right);
}
if(right > left){
permute(permutations, paren + ")", left, right--);
}
}
}
algorithm recursion backtracking parentheses
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
add a comment |
I have been trying to program the Generate Parenthesis problem on Leetcode, but I keep on getting "Memory Limit Exceeds", which means that I have an infinite loop in my code. However, I cannot understand why there will be infinite loop/recursion. Thank you!
class Solution {
public List<String> generateParenthesis(int n) {
List<String> permutations = new ArrayList<String>();
permute(permutations, "" , n, n);
return permutations;
}
public void permute (List<String> permutations, String paren, int left, int right){
if(left == 0 && right == 0){
permutations.add(paren);
return;
}
if(left > 0){
permute(permutations, paren + "(", left--, right);
}
if(right > left){
permute(permutations, paren + ")", left, right--);
}
}
}
algorithm recursion backtracking parentheses
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
add a comment |
I have been trying to program the Generate Parenthesis problem on Leetcode, but I keep on getting "Memory Limit Exceeds", which means that I have an infinite loop in my code. However, I cannot understand why there will be infinite loop/recursion. Thank you!
class Solution {
public List<String> generateParenthesis(int n) {
List<String> permutations = new ArrayList<String>();
permute(permutations, "" , n, n);
return permutations;
}
public void permute (List<String> permutations, String paren, int left, int right){
if(left == 0 && right == 0){
permutations.add(paren);
return;
}
if(left > 0){
permute(permutations, paren + "(", left--, right);
}
if(right > left){
permute(permutations, paren + ")", left, right--);
}
}
}
algorithm recursion backtracking parentheses
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
I have been trying to program the Generate Parenthesis problem on Leetcode, but I keep on getting "Memory Limit Exceeds", which means that I have an infinite loop in my code. However, I cannot understand why there will be infinite loop/recursion. Thank you!
class Solution {
public List<String> generateParenthesis(int n) {
List<String> permutations = new ArrayList<String>();
permute(permutations, "" , n, n);
return permutations;
}
public void permute (List<String> permutations, String paren, int left, int right){
if(left == 0 && right == 0){
permutations.add(paren);
return;
}
if(left > 0){
permute(permutations, paren + "(", left--, right);
}
if(right > left){
permute(permutations, paren + ")", left, right--);
}
}
}
algorithm recursion backtracking parentheses
algorithm recursion backtracking parentheses
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
asked Nov 21 '18 at 0:53
Jennifer ZhouJennifer Zhou
778
778
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
You are calling with parameter left-- it will call the method again with the same value for the parameter left; only after your function returns, the parameter left is reduced by one.
But this is also not going to solve your problem, you have to supply left-1 like :
permute(permutations, paren + "(", left-1, right);
and similarly for right:
permute(permutations, paren + ")", left, right-1);
left-- reduces the value when the function returns which is not what you want.
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You are calling with parameter left-- it will call the method again with the same value for the parameter left; only after your function returns, the parameter left is reduced by one.
But this is also not going to solve your problem, you have to supply left-1 like :
permute(permutations, paren + "(", left-1, right);
and similarly for right:
permute(permutations, paren + ")", left, right-1);
left-- reduces the value when the function returns which is not what you want.
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
add a comment |
You are calling with parameter left-- it will call the method again with the same value for the parameter left; only after your function returns, the parameter left is reduced by one.
But this is also not going to solve your problem, you have to supply left-1 like :
permute(permutations, paren + "(", left-1, right);
and similarly for right:
permute(permutations, paren + ")", left, right-1);
left-- reduces the value when the function returns which is not what you want.
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
add a comment |
You are calling with parameter left-- it will call the method again with the same value for the parameter left; only after your function returns, the parameter left is reduced by one.
But this is also not going to solve your problem, you have to supply left-1 like :
permute(permutations, paren + "(", left-1, right);
and similarly for right:
permute(permutations, paren + ")", left, right-1);
left-- reduces the value when the function returns which is not what you want.
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
You are calling with parameter left-- it will call the method again with the same value for the parameter left; only after your function returns, the parameter left is reduced by one.
But this is also not going to solve your problem, you have to supply left-1 like :
permute(permutations, paren + "(", left-1, right);
and similarly for right:
permute(permutations, paren + ")", left, right-1);
left-- reduces the value when the function returns which is not what you want.
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
answered Nov 21 '18 at 2:26
SomeDudeSomeDude
4,39331427
4,39331427
add a comment |
add a comment |
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