Recommender Systems by User-based Collaborative Filtering

[ngtduc693]

This PR introduces a User-based Collaborative Filtering algorithm implemented in C#. The algorithm predicts a user's rating for a given item based on ratings from other users with similar preferences. The main components of this PR include

CollaborativeFiltering included:

• CalculateSimilarity: Computes the similarity between two users based on their shared item ratings using the Pearson correlation coefficient.
• PredictRating: Using ratings from other users who have rated the same item, it forecasts a target user's rating for a particular item. The prediction is a weighted sum determined by user similarity.

• I have performed a self-review of my code
• My code follows the style guidelines of this project
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Comments in areas I changed are up to date
• I have added comments to hard-to-understand areas of my code
• I have made corresponding changes to the README.md

[ngtduc693]

First time attending hacktoberfest 2024, and this is my first PR, I hope everything goes well 😃

[siriak]

Looks good, thanks!

[codecov]

Codecov Report

Attention: Patch coverage is 97.77778% with 1 line in your changes missing coverage. Please review.

Project coverage is 95.02%. Comparing base (7f6eed4) to head (8397f46).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...rithms/RecommenderSystem/CollaborativeFiltering.cs	97.77%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #483      +/-   ##
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+ Coverage   95.01%   95.02%   +0.01%     
==========================================
  Files         254      255       +1     
  Lines       10570    10615      +45     
  Branches     1491     1497       +6     
==========================================
+ Hits        10043    10087      +44     
  Misses        403      403              
- Partials      124      125       +1     

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[siriak]

Please increase test coverage

[ngtduc693]

Hi @siriak , I just added some test cases to increase the test coverage percent

Thanks for your help to review

[siriak]

Looks good, thanks!