Array-2 solution

[Simranb10]

No description provided.

[super30admin]

Disappeared Numbers (FindDisappearedNumbers.java)

Strengths:

• Excellent time complexity of O(n), significantly better than the reference solution's O(n²)
• Uses in-place array modification, achieving O(1) space complexity (excluding output)
• Correctly handles the marking and restoration of array values
• Clean, readable code structure with meaningful variable names

Areas for Improvement:

• The class-level result field could be local to the method for better encapsulation
• Consider adding input validation (null check, empty array check)
• The second loop mixes restoration of original values with result collection; separating these concerns would improve readability
• Could add comments explaining the marking strategy for future maintainability

Minor Optimization:

• The restoration loop in the second pass is unnecessary if the problem allows modifying the input array (which the follow-up suggests). Keeping the original approach is fine, but could be simplified if input modification is acceptable.

VERDICT: PASS

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max and min (GetMinMax.java)

Strengths:

• The algorithm correctly implements the efficient pairwise comparison approach, achieving O(n) time with approximately 3*(N/2) comparisons, which is less than 2*(N-2) as required
• Good handling of edge cases (empty arrays would need consideration, but the core logic is sound)
• Clean and readable code structure with appropriate variable naming
• Correctly handles both even and odd length arrays

Areas for Improvement:

• The return type uses ArrayList<Integer> when a simple int[] array would be more appropriate and efficient (avoids autoboxing overhead)
• The import java.util.List is unused (only ArrayList is needed)
• For production code, consider adding input validation for edge cases like null or empty arrays
• The comment style could be improved to be more descriptive

Minor Optimization:

• Using primitive int[] instead of ArrayList<Integer> would eliminate autoboxing overhead, making it slightly more efficient

Overall, this is a solid solution that correctly solves the problem with optimal time complexity.

VERDICT: PASS

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Life Game (GameOfLife.java)

Strengths:

• Correctly implements the in-place algorithm using intermediate states
• Good use of comments to explain the encoding scheme (2: live→dead, 3: dead→live)
• Clear variable naming (m, n, r, c, live)
• Properly handles boundary conditions with the bounds check
• Includes both original live cells (1) and dying cells (2) in neighbor count, which is crucial for correctness

Areas for minor improvement:

• The directions array could be declared as static final since it doesn't change, which would be slightly more memory-efficient
• Could consider extracting the neighbor counting into a helper method for better modularity (though the reference solution also uses inline counting)

Overall, this is a solid implementation that correctly solves the problem with optimal time and space complexity.

VERDICT: PASS