solution to both problems

[avishwak]

No description provided.

[super30admin]

1. Correctness:

• For Problem 1 (Top Travellers), the solution correctly joins the users and rides tables, handles NULL distances with ifnull, and groups by user ID. The ordering is also correct.
• For Problem 2 (ApplesAndOranges), the student provided three solutions. The first uses CTEs which is correct but verbose. The second is a simple join but might be less readable. The third solution using CASE statements is the most elegant and efficient.

2. Time Complexity:

• Problem 1: O(n log n) due to the GROUP BY and ORDER BY operations.
• Problem 2: All solutions are O(n) for the join operations, with the CASE statement version likely being the most efficient as it requires only one pass through the data.

3. Space Complexity:

• Problem 1: O(n) for storing intermediate results.
• Problem 2: The CTE version uses more space than the other solutions. The CASE statement version is most space-efficient.

4. Code Quality:

• The code is generally well-structured and readable.
• Good use of comments to separate different solutions.
• Consistent formatting and indentation.
• The CASE statement solution demonstrates better SQL practices than the other versions.

5. Efficiency:

• Problem 1 is already optimal.
• For Problem 2, the student correctly identified the most efficient solution (CASE statement version) and included it.
• The CTE version could be simplified as shown in the final solution.

Areas for improvement:

• The CTE solution for Problem 2 could be removed since it's less efficient than the other solutions provided.
• Adding comments explaining why one solution is better than others would be helpful for learning purposes.