Added newAdded QuickSelect Algorithm for Kth Largest Element + Benchmark and Documentation files quickselect.cpp readme.md and compare_method.cpp also…

[omuphade77]

… fix binary search

🔍 Summary

This pull request adds a new implementation of the QuickSelect algorithm to efficiently find the Kth largest element in an array.
It also includes a benchmark comparison script and README documentation for better understanding and testing.

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🧩 Files Added

• quickselect.cpp → Implements the QuickSelect algorithm (average O(n) time)
• compare_methods.cpp → Benchmarks Sorting, nth_element, and QuickSelect methods
• README.md → Detailed explanation, complexity table, and usage instructions

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⚙️ Features

• New algorithm with linear average time complexity.
• Performance comparison between existing methods.
• Clear documentation for new contributors.
• Consistent naming and code formatting.

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🧠 Improvements / Benefits

• Provides a faster alternative to heap-based methods.
• Encourages modular code and benchmarking.
• Makes the “Kth Largest” folder more complete and educational for contributors.

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✅ Testing

Tested locally on multiple input arrays:
Input: [3,2,3,1,2,4,5,5,6], k=4
Output: 4
Results from all methods are consistent.

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📈 Future Enhancements

• Add randomized and median-of-medians versions of QuickSelect.
• Integrate automated test file (test_kth_largest.cpp).
• Visualize runtime using a Python plot.

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Closes:

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