Implement Array-1: Self Product,and Diagonal and Spiral Matrix

[ashutoshweb]

1. Self Product
2. Diagonal Matrix
3. Spiral Matrix

[super30admin]

Product Except Self (Product.java)

Strengths:

• Excellent time complexity of O(n), which is optimal for this problem
• Achieves O(1) extra space complexity (excluding output array), meeting the follow-up requirement
• Clean, readable code with good comments explaining the approach
• Correctly handles the algorithm without using division
• Proper initialization of variables (result[0] = 1, rightProduct = 1)

Areas for Improvement:

• The variable leftProduct is declared but never used - consider removing it for cleaner code
• Could add a brief explanation of how the two-pass technique avoids division
• Consider adding comments for edge cases to improve code documentation

Minor Optimization:

• The leftProduct array declaration is unnecessary and could be removed to slightly reduce memory usage (though it doesn't affect space complexity since it's O(n) regardless)

VERDICT: PASS

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Diagonal Traverse (DiagonalMatrix.java)

Strengths:

• Excellent input validation with appropriate exception handling and early returns
• Very clear and descriptive comments explaining each condition
• Proper handling of corner cases (checking column boundary before row boundary when moving up, and row boundary before column when moving down)
• Clean and readable code structure
• Good variable naming convention
• The solution follows the same efficient approach as the reference solution

Areas for Improvement:

• The solution is functionally complete and well-written. Minor observations:
  • Could potentially use int direction = 1 instead of boolean up for consistency with the reference solution, but this is purely stylistic
  • The comments are comprehensive but could be slightly more concise without losing clarity

This is a solid, production-quality solution that demonstrates good understanding of the algorithm and clean coding practices.

VERDICT: PASS

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Spiral Matrix (SpiralMatrix.java)

Strengths:

• Clean and readable implementation of the four-directional traversal
• Proper handling of edge cases (odd-dimension matrices) with conditional checks
• Good variable naming convention
• Well-documented with comments explaining the approach
• Correct time and space complexity

Areas for Improvement:

• The class name SpiralMatrix is fine, but for LeetCode submissions, consider naming it Solution to match the standard format
• The comment header format could be improved to match standard documentation style
• Consider adding a brief comment within the while loop to clarify the four traversal phases

The solution is functionally equivalent to the reference solution and demonstrates a solid understanding of the algorithm.

VERDICT: PASS