Create add_binary.py

[Sujalgupta2p]

This program adds two binary numbers given as strings and returns their sum as a binary string. Based on LeetCode Problem 67 — Add Binary.
This program adds two binary numbers given as strings and returns their sum as a binary string.

About

This algorithm solves the problem of adding two binary numbers without using built-in base conversion functions.
It is based on LeetCode Problem 67 — Add Binary.

How it works

1. Traverse both strings from right to left (least significant bit first).
2. Add corresponding bits plus the carry.
3. Append (sum % 2) to the result and update carry = sum // 2.
4. Reverse the final result to get the correct binary sum.

Example

Reference

https://en.wikipedia.org/wiki/Binary_arithmetic

✅ 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.
• All new Python files are placed inside an existing directory.
• All filenames are lowercase characters with underscores (no spaces or dashes).
• All functions and variable names follow Python naming conventions (snake_case).
• 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 explanation.

[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]

As there is no test file in this pull request nor any test function or class in the file bit_manipulation/add_binary.py, please provide doctest for the function addBinary

Variable and function names should follow the snake_case naming convention. Please update the following name accordingly: addBinary

Please provide descriptive name for the parameter: a

Please provide descriptive name for the parameter: b