Add A* Search Algorithm for Weighted Graph Pathfinding

[surajdm123]

Summary

This PR introduces an implementation of the A* (A-Star) search algorithm for weighted graph pathfinding, added under the existing search algorithms module.

The A* algorithm is a widely used heuristic-based search technique that combines the benefits of Dijkstra’s algorithm and greedy best-first search to efficiently compute optimal paths in weighted graphs.

Why this addition is useful

A* is a foundational algorithm used in:

• AI Algorithms
• Navigation systems (e.g., shortest route computation)
• Game AI pathfinding
• Robotics and planning systems
• General graph optimization problems

Adding this algorithm improves the completeness of the search algorithms module by covering heuristic-based informed search techniques, complementing existing BFS, DFS, and uninformed search implementations.

Testing

Checklist

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new algorithms include a corresponding test class that validates their functionality.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

❌ Patch coverage is 93.18182% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.54%. Comparing base (227355e) to head (18a2009).
⚠️ Report is 17 commits behind head on master.

Files with missing lines	Patch %	Lines
...ain/java/com/thealgorithms/others/AStarSearch.java	93.18%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7374      +/-   ##
============================================
+ Coverage     79.47%   79.54%   +0.07%     
- Complexity     7090     7152      +62     
============================================
  Files           791      797       +6     
  Lines         23202    23412     +210     
  Branches       4565     4604      +39     
============================================
+ Hits          18439    18624     +185     
- Misses         4024     4050      +26     
+ Partials        739      738       -1     

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