Added Huffman Coding Problem

[pratikscfr]

Description

Added a solution to famous Huffman Coding Problem, which is a greedy algorithm.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• [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
• [ ] I have made corresponding changes to the documentation
• [ ] Any dependent changes have been merged and published in downstream modules
• [ ] I have squashed unnecessary commits

[pratikscfr]

Changes added to the code according to format.