Reversing a queue

[stutimohta20]

What would you like to share?

Reversing a queue using a stack in cpp language

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[stutimohta20]

Please assign this to me

[webbdays]

Just swapping the start and end variables of queue is enough to reverse the queue.
It is straight forward.
I think using stack is unnecessary here.
But still it's your wish.

And this repository is the collection for all algorithms in Cpp.
So, yes you can also use stack here.
It's another method to reverse the queue.

[MartinKing-star]

is there any optimal way to solve this problem ?

[webbdays]

Yes.
But it depends.
Option 1:
When implementing the queue,

If using contiguous array or doubly linked list, then add reverse method that swaps the start and end variables/pointers of the queue. Which takes time => O(1) and space => O(1).

If using forward linked list, then we have to reverse the links(reverse the linked list). Which takes time => O(n) and space => O(1).

Option 2:
If using the std queue or the queue that is already implemented (if we cannot implement the queue) , then in that case we can use stack. Which takes time => O(2*n) => O(n) and space => O(n).

Reminder : I am not 100% sure whether the method used for option2 is optimal method.(some one else please confirm).

It also depends on whether the popfront, pushback methods are acceptable. But these will not obey the queue ethics. (We cannot allow a person joining in the front of the queue unless those people in queue have good generosity. That will change the meaning of the queue).

[saquib678]

I want to work on this issue, Please assign this to me.

[sng125]

Hi! If this is still active, can I try working on this?

[Panquesito7]

Anyone of you, feel free to make a PR! Let us know if you need any help. 🙂

[alecrothenberg]

Hi! is this issue still available and if so can I be assigned to this?

[alecrothenberg]

I just submitted a pull request for this issue, please let me know if I should make any changes to it!

[aryantalekar20]

I would like to work on this one if it is still open.

[EitanKog]

I created a reverse_queue file, please check it