Add new algorithm index_2d_array_in_1d

[edy252]

Describe your change:

• 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.
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[algorithms-keeper]

Click here to look at the relevant links ⬇️

🔗 Relevant Links

Repository:

• Contributing guidelines
• Project Euler solution guidelines

Python:

• Formatted string literals (f-strings)
• Type hints
• doctest
• unittest
• pytest

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[algorithms-keeper]

Please provide return type hint for the function: __init__. If the function does not return a value, please provide the type hint as: def function() -> None:

[cclauss]

@dataclass
class Index2DArrayIterator:
    matrix: list[list[int]]
    def __iter__(self) -> Iterator[int]:
        for row in self.matrix:
            yield from row

[edy252]

@dataclass
class Index2DArrayIterator:
    matrix: list[list[int]]
    def __iter__(self) -> Iterator[int]:
        for row in self.matrix:
            yield from row

Thank you for the review! Did not know about the dataclass decorator, will definitely be using it in my python classes from now on!