Add Pollard's Rho for discrete logarithm #13656

[anshmittal2004]

Closes #13656

Added Pollard's Rho algorithm for discrete logarithm in maths/.

• Implements pollards_rho_discrete_log(g, h, p) as requested.
• Uses Brent's cycle detection for O(√p) expected time.
• Includes docstring with example (2^11 % 29 = 22) and complexity.
• Handles small primes; probabilistic with retry on failure.
• Added test cases for examples (g=2, h=22, p=29 and g=5, h=12, p=13).

[Hacktoberfest 2025 contribution]

Checklist

• I have read the contribution guidelines.
• The submitted code is in compliance with The Algorithms "Code quality" guidelines.
• I have added a description to my changes.
• I have added tests for the implementation.
• I have added an explanation to my implementation. # Optional, add later if required
• The code is not plagiarized and my own implementation.
• The code is submitted to the correct issue.
• I have run black to format the code.
• I have run mypy to check for type hints.
• I have read the README and the DIRECTORY and the submitted code is not duplicated.

[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 maths/pollard_rho_discrete_log.py, please provide doctest for the function pollards_rho_discrete_log

Please provide descriptive name for the parameter: g

Please provide descriptive name for the parameter: h

Please provide descriptive name for the parameter: p

[algorithms-keeper]

Please provide descriptive name for the function: f

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

Please provide descriptive name for the parameter: x

Please provide descriptive name for the parameter: y