Implement Queue using 2 stacks

[PavanKaushikAduri]

No description provided.

[super30admin]

Implement Queue using Stacks (queue_using_two_stacks.py)

Great work! Your solution correctly implements a queue using two stacks with the same time and space complexity as the reference solution. The logic is sound and the code is readable.

A few minor suggestions:

1. Dead code: The return -1 at the end of peek() is unreachable since both if/else branches return values. You can remove it for cleaner code.
2. Code style: Consider following the reference pattern where pop() calls peek() to ensure the output stack is populated. This reduces code duplication:

   def pop(self) -> int:
       self.peek()  # ensures stack2 is populated
       return self.stack2.pop()

3. Comments: Your comments are good, but you could add a brief explanation of the two-stack approach (why it works) for future readers.

VERDICT: PASS

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Design HashMap (design_hashmap.py)

Strengths:

1. Correct implementation: Your solution correctly implements all required operations (put, get, remove) using separate chaining with linked lists.
2. Clean code structure: The code is well-organized with a separate ListNode class and clear method definitions.
3. Good use of dummy head: Using a dummy head node simplifies the linked list operations, similar to the reference solution.
4. Proper comments: The header comments clearly state the time/space complexity and confirm successful execution.
5. Readable variable names: Variables like keyHash, prevNode, and primaryarray are descriptive.

Areas for improvement:

1. Bucket size: You chose 10000 buckets while the reference uses 1000. While both work, consider the trade-off between memory usage and collision probability. With 10000 buckets and at most 10^4 operations, you'll have very few collisions but use more memory.
2. getPrevNode return value: The function returns None when the head matches the key, which works because of the dummy node pattern. However, this could be confusing. Consider adding a comment explaining this behavior.
3. Edge case handling: Consider adding explicit handling for edge cases like empty storage in remove (you do check this, which is good).
4. Type hints: The type hints are good, but consider adding return type hints for getPrevNode for clarity.
5. Magic numbers: The bucket size (10000) is a magic number. Consider making it a class constant or explaining why this size was chosen.

Overall, this is a solid implementation that correctly solves the problem with good time and space complexity.

VERDICT: PASS