Add algorithms for 2Sum, 3Sum, Kadane's Algorithm, and linked list pr…

[karankumar12345]

• Add an algorithm
• Fix a bug or typo in an existing algorithm
• Documentation change

Description:
This pull request adds algorithms for 2Sum, 3Sum, Kadane's Algorithm, and linked list problems including finding the intersection point and implementing the slow-fast pointer technique.

1. 2Sum Algorithm: Finds two numbers in an array that add up to a specified target sum using a hash map for efficient lookups.
2. 3Sum Algorithm: Identifies all unique triplets in the array that sum to zero.
3. Kadane's Algorithm: Efficiently computes the maximum sum of a contiguous subarray.
4. Linked List Problems:
   • FindIntersectionPoint: Determines the intersection point of two linked lists.
   • SlowFast: Implements the slow-fast pointer technique to detect cycles in a linked list.

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. To ease review, please open separate PRs for separate algorithms.
• All new JavaScript files are placed inside an existing directory.
• All filenames use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames.
  Example: UserProfile.js is allowed but userprofile.js, Userprofile.js, user-Profile.js, userProfile.js are not.
• All new algorithms have a URL in their comments that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues, then the commit message contains Fixes: #{$ISSUE_NO}. (Replace {$ISSUE_NO} with the actual issue number if applicable)
  .

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.77%. Comparing base (18da83a) to head (2029064).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1716      +/-   ##
==========================================
+ Coverage   84.65%   84.77%   +0.11%     
==========================================
  Files         378      382       +4     
  Lines       19744    19895     +151     
  Branches     2951     2978      +27     
==========================================
+ Hits        16715    16866     +151     
  Misses       3029     3029              

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[appgurueu]

1. Please ideally keep it to one PR per addition, unless the algorithms are related.
2. Please get rid of redundant algorithms. We already have Kadane's Algorithm for example.
3. Try to make your algorithms compatible with existing data structures, e.g. our linked list implementation.
4. CI is failing.