Queue implementation using two Stacks

[amirsoroush]

Queue using two Stacks:

Here is the implementation of Queue using two stacks. It has O(1) time complexity for en-queuing and Amortized O(1) for de-queuing. The worst case time complexity for de-queuing is O(n) though. The rationale behind this and its use-cases are mentioned here and here.

I also included doctest for methods. It's formatted using "Black" and checked by "Mypy".

---

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[amirsoroush]

Apparently ruff is not happy with my commit. It says:

Error: computer_vision/lenet_pytorch.py:9:8: PLR0402 Use `from torch import nn` in lieu of alias
Error: Process completed with exit code 1.

Unfortunately I have no idea about it. I didn't import anything from torch.

[CaedenPH]

Apparently ruff is not happy with my commit. It says:

Error: computer_vision/lenet_pytorch.py:9:8: PLR0402 Use `from torch import nn` in lieu of alias
Error: Process completed with exit code 1.

Unfortunately I have no idea about it. I didn't import anything from torch.

Seems like you didn't touch that file so someone must've merged a commit that failed ruff

[amirsoroush]

@CaedenPH I guess the failure is because of the merged commit which is currently requested to be reverted here.

[cclauss]

For readability, please move the "magic" functions like .__len__() and .str()before.get()and.put()`

[cclauss]

LGTM

A few changes:

• If you can use something immediately without naming it then do so to keep doctests short
• Test the result, not the result == expected is True
• Use repr() instead of str() in tests unless essential.
• Favor tuples over lists when possible because they take less RAM.
• We do not need a .size()` method if we have defined len.
• The filename should match the class that is inside it.

[amirsoroush]

@cclauss Thank you for your advice and also for introducing me to ruff linter.

For .size(), "result == expected is True", "implementing __str__", I wanna say that I wrote them because they've been implemented in other files. I tried to be consistent with those but I'm totally agree with you. I'll also fix those in the future.

[cclauss]

Thanks for your contribution. Our codebase is not (yet) perfect so please submit pull requests for any existing algorithms that can be improved.