Add smooth algorithm

[mohmmadAyesh]

Describe your change:

• [x ] Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• [ x] I have read CONTRIBUTING.md.
• [ x] This pull request is all my own work -- I have not plagiarized.
• [x ] I know that pull requests will not be merged if they fail the automated tests.
• [ x] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [ x] All new Python files are placed inside an existing directory.
• [ x] All filenames are in all lowercase characters with no spaces or dashes.
• [ x] All functions and variable names follow Python naming conventions.
• [ x] All function parameters and return values are annotated with Python type hints.
• [ x] All functions have doctests that pass the automated testing.
• [ x] 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 description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[mohmmadAyesh]

@cclauss Hi can you review this PR or any of maintainer and merge if it has not required any further suggested changes?

[tianyizheng02]

I found this GeeksforGeeks article with nearly identical code. The only differences appear to be comments and some function and variable names. I'm not flagging this as plagiarism right out of the gate because I can't definitively prove that the article was written before this PR was made, though this PR is still suspect.

@cclauss, thoughts on whether this should be flagged as plagiarism? If so, we can just close this PR. If not, I think we can let it pass with the caveat that the code must be refactored/rewritten and more thoroughly documented.

[tianyizheng02]

I'll take this to mean that we're flagging this PR for plagiarism and add the appropriate tag