add exponential search algorithm

[kiarash8112]

Describe your change:

added exponential algorithm using binary_search_recursion also tests and docs about it

• 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:

• 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 description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[cclauss]

Nice addition!

For optional extra credit, add a timeit benchmark to show relative performance.

[cclauss]

I am not a fan of functions that return multiple datatypes. If the search fails, let's return -1 (like "Hello".find("Z")) or raise a ValueError (like "Hello".index("Z")).

Suggested change

	def exponential_search(sorted_collection: list[int], item: int) -> int | None:
	def exponential_search(sorted_collection: list[int], item: int) -> int:

[cclauss]

I thought more about sorting the sorted collection… it is a bad idea. The second item in might be different in the two lists so the function might tell me that is the second item when in my list it is the third item. So, the implementations should raise ValueError on unsorted input.

[cclauss]

This is a really slick addition. Thanks for doing it!

[kiarash8112]

@cclauss thank you for your suggestions :)

[tianyizheng02]

@cclauss Since exponential search is a different algorithm from binary search, why was it placed in the binary_search.py file? Shouldn't it have gotten its own file?

[cclauss]

@tianyizheng02 exponential_search() embeds a call to binary_search_by_recursion() but as the benchmarks demonstrate delivers a faster result. Looking at the first commit makes this clearer.