Reduced time complexity for reversing a string

[pritam-dash]

Added a third way of reversing a string, which reduces the time complexity of the code.

Describe your change:

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

References

Checklist:

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized it.
• [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 Java files are placed inside an existing directory.
• [ ] All filenames are in all uppercase characters with no spaces or dashes.
• [x] All functions and variable names follow Java naming conventions.
• [ ] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [ ] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[pritam-dash]

Can you kindly elaborate on the upgrades that you are looking for? It would help me to further integrate the desired tests with curated results.

[siriak]

JUnit tests https://www.tutorialspoint.com/junit/junit_test_framework.htm

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This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

Please reopen this pull request once you commit the changes requested or make improvements on the code. If this is not the case and you need some help, feel free to seek help from our Gitter or ping one of the reviewers. Thank you for your contributions!