Completed Pandas4

[Paneripatel]

No description provided.

[super30admin]

The student's solution demonstrates a good understanding of pandas operations and ranking methods to solve the problems of finding the Nth highest and second highest salaries. Here are some detailed observations:

1. Correctness:

   • Both solutions correctly handle duplicate salaries by dropping duplicates before ranking.
   • The solutions properly handle edge cases where there might not be enough distinct salaries (returning None or NaN appropriately).
   • The ranking logic using method='dense' is appropriate for this type of problem.

2. Time Complexity:

   • The time complexity is O(n log n) due to the ranking operation, which is efficient for this type of problem.
   • The drop_duplicates operation is O(n) in the worst case.

3. Space Complexity:

   • The space complexity is O(n) as we're creating new columns for ranking and potentially storing filtered results.

4. Code Quality:

   • The code is generally well-structured and readable.
   • Variable names are clear and descriptive.
   • The solutions follow pandas best practices for DataFrame operations.
   • One minor improvement could be to use consistent naming between the two solutions (e.g., either always use 'rnk' or 'rank').

5. Efficiency:

   • The solutions are already quite efficient for typical use cases.
   • One potential optimization could be to avoid creating a new column for ranking if we only need it temporarily (though this is a minor point).

6. Edge Cases:

   • Both solutions handle cases where N is larger than the number of distinct salaries.
   • The second solution specifically checks if there are at least 2 distinct salaries before proceeding.

7. Suggestions:

   • Consider adding docstrings to explain the function parameters and return values.
   • The import of numpy in the second solution isn't strictly necessary since pandas can handle NaN values directly.
   • The solutions could be made more consistent in their return value formatting (one uses None, the other uses NaN).