Sql4 Completed

[HaswathaSridharan]

No description provided.

[super30admin]

1. Correctness:

   • Problem 1: The solution correctly uses a CTE with window functions to calculate running sums and then filters based on the budget constraint. The logic for handling both Senior and Junior candidates appears correct.
   • Problem 2: The solution correctly handles the league statistics by considering both home and away matches and calculating the required metrics. The ordering is also correctly implemented.
   • Problem 3: The solution correctly identifies salespersons who didn't have orders with 'RED' company using a NOT IN subquery.
   • Problem 4: The solution correctly counts friend requests and acceptances using UNION ALL and finds the maximum count.

2. Time Complexity:

   • Problem 1: O(n log n) due to the sorting in the window function.
   • Problem 2: O(n) for the UNION ALL and O(n log n) for the GROUP BY and sorting.
   • Problem 3: O(n) for the subquery and main query.
   • Problem 4: O(n) for the CTE and O(n) for the aggregation.

3. Space Complexity:

   • Problem 1: O(n) for storing the CTE.
   • Problem 2: O(n) for storing the CTE and intermediate results.
   • Problem 3: O(n) for storing the subquery results.
   • Problem 4: O(n) for storing the CTE and aggregation results.

4. Code Quality:

   • The code is generally well-structured and readable.
   • Consistent use of CTEs improves readability.
   • Some minor improvements could be made:
     • Problem 1: The column alias 'rsum' could be more descriptive.
     • Problem 4: There's a typo in 'SELECt' which should be 'SELECT'.
     • Consistent indentation and spacing would improve readability further.

5. Efficiency:

   • The solutions are already quite efficient, but for Problem 1, the window function could be optimized by pre-filtering Senior candidates before calculating the running sum for Juniors.
   • For Problem 4, the LIMIT 1 is good practice since there could be ties for maximum friends.