MockSQL3_Complete_RN32MAY2025DS

[Feminto]

No description provided.

[super30admin]

The student has provided two solutions for the Market Analysis II problem and one solution for the Tournament Winners problem. Here's my evaluation:

1. Correctness:

   • For Market Analysis II, both methods appear to correctly identify whether a seller's second item sold was their favorite brand. Method 1 is more complex but handles edge cases better (like sellers with only one item). Method 2 is simpler but might miss some edge cases.
   • For Tournament Winners, the solution correctly identifies the highest-scoring player in each group, with proper tie-breaking by player_id.

2. Time Complexity:

   • Market Analysis II methods both use window functions and joins, resulting in O(n log n) complexity.
   • Tournament Winners uses a UNION ALL and window function, also O(n log n) complexity.
   • All solutions have reasonable time complexity for typical SQL problems.

3. Space Complexity:

   • All solutions create temporary tables (CTEs) which use additional space, but this is standard practice in SQL.
   • The space usage is proportional to the input size, which is acceptable.

4. Code Quality:

   • Generally good with clear CTE naming and structure.
   • Some minor issues:
     • In Market Analysis II, the column alias "2nd_item_fav_brand" uses numbers which might cause issues in some SQL dialects (better to use words).
     • The Tournament Winners solution could benefit from a comment explaining the tie-breaker logic more clearly.
     • Consistent indentation could be improved in some places.

5. Efficiency:

   • Market Analysis II Method 1 could be simplified by directly filtering for the second order rather than using ROW_NUMBER and then filtering.
   • The Tournament Winners solution is quite efficient and well-structured.

Overall, the solutions are correct and demonstrate good SQL skills. The main areas for improvement are code style consistency and potentially simplifying some of the logic.