completed binary search - 1

[yashhh-23]

No description provided.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds Java implementations of common binary-search variants (rotated sorted array search, “infinite” sorted array search via reader, and 2D matrix search).

Changes:

• Added rotated sorted array binary search solution.
• Added exponential-range + binary search solution using an ArrayReader.
• Added 2D matrix binary search by flattening indices.

Reviewed changes

Copilot reviewed 3 out of 5 changed files in this pull request and generated 6 comments.

File	Description
RotatedSortedArray.java	Introduces rotated-array binary search implementation and a local main driver.
InfinitSortedArray.java	Introduces “infinite array” search using ArrayReader, plus a local main and reader implementation.
2DMatrixSearch.java	Introduces matrix binary search treating the matrix as a 1D sorted array.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[super30admin]

Search inside a Rotated Sorted Array (RotatedSortedArray.java)

Strengths:

• Correctly implements the binary search algorithm for rotated sorted arrays
• Good edge case handling (null/empty array check)
• Clear and descriptive variable names
• Well-commented code explaining the approach
• Proper use of left + (right - left) / 2 to prevent integer overflow
• Includes a test harness in main method for verification

Areas for Improvement:

• The condition target >= nums[left] could be simplified to target >= nums[left] (already correct) or just target >= nums[left] (redundant check)
• Consider adding comments explaining the logic of why we check target < nums[mid] vs target > nums[mid] for the sorted halves
• The test output could be more descriptive

The solution is functionally correct and efficient. It matches the reference solution in both approach and complexity.

VERDICT: PASS

---

Search Inside a Sorted Array whose Length is unknown (InfinitSortedArray.java)

Strengths:

• Correctly implements the two-phase approach (exponential search + binary search)
• Good use of comments explaining the approach in three sentences as requested
• Clean code structure with proper variable naming
• Includes a working ArrayReader implementation for testing
• Handles edge cases (null array, out-of-bounds indices)

Areas for Improvement:

• The comment "where n is the index of the target element" for time complexity is slightly imprecise; it should simply state O(log n) where n is the array length
• The ArrayReader returns Integer.MAX_VALUE for out-of-bounds, but the problem specifies 2^31 - 1; while functionally equivalent, matching the problem specification exactly would be more precise
• Could add input validation in the main method

VERDICT: PASS

---

Search a 2D Matrix (2DMatrixSearch.java)

Strengths:

• Correctly implements the binary search algorithm on a 2D matrix
• Good use of the overflow-safe mid calculation: low + (high - low)/2
• Clean, readable code with appropriate comments
• Matches the reference solution exactly, demonstrating understanding of the approach

Areas for Improvement:

• The comment "compare with target tp get the result" contains a typo ("tp" should be "to")
• Could add a brief comment explaining why treating the matrix as 1D is valid (rows are sorted and first element of each row is greater than last element of previous row)

VERDICT: PASS