Pandas10: Problem Solutions_RN32MAY2025DS

[Feminto]

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[super30admin]

The student has provided two methods to solve the problem, which demonstrates good problem-solving approach by considering different approaches.

1. Correctness: Both methods appear to solve the problem correctly. Method 1 uses a dictionary to group products by sell date and then processes the results, while Method 2 uses pandas' groupby and aggregation functions, which is more idiomatic for pandas operations. Both methods handle the grouping and counting of unique products correctly.

2. Time Complexity:

   • Method 1: O(n) for the initial loop to build the dictionary, plus O(m * k log k) where m is the number of unique dates and k is the average number of products per date (for sorting). Overall O(n + m * k log k).
   • Method 2: The groupby operation is typically O(n), and the aggregation operations are O(n) for nunique and O(m * k log k) for the sorted join. Similar complexity to Method 1 but more optimized due to pandas' internal optimizations.

3. Space Complexity:

   • Both methods require O(n) space to store the intermediate data structures (dictionary in Method 1, groupby object in Method 2).

4. Code Quality:

   • Both methods are well-structured and readable.
   • Method 2 is more concise and leverages pandas' built-in functions effectively, which is generally preferred for pandas operations.
   • The comments in Method 2 are helpful but could be expanded to explain why certain approaches were chosen (e.g., why sorted() is used).

5. Efficiency:

   • Method 2 is more efficient in practice due to pandas' optimized groupby operations.
   • Both methods could potentially be optimized further by using more specific pandas functions or by avoiding the sorting step if the order of products is not required.

Areas for improvement:

• The docstring for the function is missing, which would help clarify the problem being solved and the expected output.
• The variable names in Method 1 could be more descriptive (e.g., 'adict' could be 'date_to_products').
• The commented-out line in Method 2 should be removed to keep the code clean.