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Create SwapWithoutTemp #1580

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imshreya2000
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Describe your change:

  • 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 JavaScript files are placed inside an existing directory.
  • All filenames should use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames.
    Example:UserProfile.js is allowed but userprofile.js,Userprofile.js,user-Profile.js,userProfile.js are not
  • All new algorithms have a URL in their comments 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}.

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@appgurueu appgurueu left a comment

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This boils down to

a ^= b
b ^= a // a ^ b ^ b = a
a ^= b // a^b^a = b

This is a nifty trick to know when for some reason, you need to avoid temporary variables / registers at all costs. But even then it's not necessarily useful; on x86 for example, alternative instructions like XCHG tend to be faster.

In JavaScript, it's not really useful; it will probably be slower than a normal swap. Also, there are no proper macros or similar; to make this function usable, you'd have to return [a, b], at which point you could just return [b, a] to swap a and b.

Besides, this is missing documentation and tests (which would fail, since JS is pass by value). Leaning towards rejection. @raklaptudirm what do you think?

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The xor trick might be good content educationally speaking. That said, this pr is definitely not up to the standards we require here and the API is faulty. I want to keep this pr open in case they can change the code and the API to work well because I would welcome the inclusion of this idea into the repo.

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3 participants