Implement stack variations

[subbaparitala9]

No description provided.

[super30admin]

The student's solution demonstrates a good understanding of data structures and their implementations. Here's a detailed evaluation:

1. Exercise_1.py (Array-based Stack):

• Correctness: The implementation correctly handles stack operations (push, pop, peek, etc.) with proper overflow/underflow checks.
• Time Complexity: Correctly identified as O(1) for all operations.
• Space Complexity: Correctly identified as O(1) for the stack operations, though O(n) for the stack storage.
• Code Quality: Well-structured with clear comments. The show() method could be modified to only show elements up to 'top' rather than the entire array.
• Efficiency: Good, though the default capacity of 1000 might be too large for some use cases.

2. Exercise_2.py (Linked List-based Stack):

• Correctness: Properly implements stack operations using linked list nodes.
• Time Complexity: Correctly identified as O(1) for push/pop operations.
• Space Complexity: Correctly identified as O(n) for the stack storage.
• Code Quality: Clean implementation. The show() method could be more pythonic by returning a string instead of printing directly.
• Efficiency: Good, though error handling could be improved (e.g., handling non-integer inputs).

3. Exercise_3.py (Singly Linked List):

• Correctness: Mostly correct, but the remove() method has a bug where it doesn't properly update the tail when removing the last node.
• Time Complexity: Correct for append (O(1) with tail pointer) and find/remove (O(n)).
• Space Complexity: Correctly identified as O(n) for the list storage.
• Code Quality: Good structure but needs better error handling (e.g., handling empty list cases).
• Efficiency: The tail pointer optimization for append is good, but the remove() method needs fixing.

General suggestions:

1. Add more edge case testing (empty structures, full structures, invalid inputs)
2. Consider adding docstrings for methods
3. The linked list remove operation needs to be fixed to properly handle tail updates
4. Consider adding type hints for better code clarity