fast exponention using bit manipulation.

[jahnavi0105]

Description

fatest exponention using bit manipulation

Type of change

• [x] New feature/question

Checklist:

• [x] My code follows the style guidelines of this project i.e. Pep8
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] Any dependent changes have been merged and published in downstream modules
• [ ] I have squashed unnecessary commits

[jahnavi0105]

I have added fast exponention using bit manipulation.