Pre course 1

[krishnavarun7]

Created stack using array, linked-list and created linked list

[super30admin]

1. Correctness:

   • Exercise_1.py: The stack implementation using a list is correct and handles basic operations (push, pop, peek, size, show) properly. The isEmpty check before pop and peek is good practice.
   • Exercise_2.py: The stack implementation using a linked list is correct. It handles push and pop operations correctly, including edge cases like popping from an empty stack.
   • Exercise_3.py: The singly linked list implementation is correct for append, find, and remove operations. The remove method handles edge cases like removing the head node or a non-existent key.

2. Time Complexity:

   • Exercise_1.py: All operations are O(1) except show() which is O(n) as it returns the entire stack.
   • Exercise_2.py: push and pop operations are O(1).
   • Exercise_3.py: append, find, and remove operations are O(n) as expected for a singly linked list.

3. Space Complexity:

   • All implementations have O(n) space complexity where n is the number of elements, which is optimal for these data structures.

4. Code Quality:

   • The code is generally well-structured and readable.
   • Some improvements could be made:
     • Add docstrings for all methods to explain their purpose and return values.
     • In Exercise_1.py, the show() method could be renamed to something more descriptive like get_stack().
     • In Exercise_3.py, the print_list method could be added to the docstring to explain its purpose.
     • Consider adding type hints for better code clarity.

5. Efficiency:

   • The implementations are efficient for their respective data structures.
   • One potential optimization in Exercise_3.py is to maintain a tail pointer to make append operations O(1) instead of O(n).