Completed Problem 1

[irrawaddy28]

No description provided.

[super30admin]

Design HashSet (Exercise_2.py)

It appears there has been a significant mix-up. The solution you provided is for the "Min Stack" problem, not the "Design HashSet" problem.

To correctly solve the Design HashSet problem, you need to:

1. Create a MyHashSet class
2. Implement three methods: add(key), remove(key), and contains(key)
3. Use a hashing strategy (like the reference solution's two-level bucketing approach, or a simpler approach using a large boolean array since keys are bounded by 10^6)

A simple approach could be:

• Use a boolean array of size 10^6 + 1
• add(key): set array[key] = True
• remove(key): set array[key] = False
• contains(key): return array[key]

Or a more space-efficient approach using bucketing as shown in the reference solution.

Please resubmit with the correct solution to the Design HashSet problem.

VERDICT: NEEDS_IMPROVEMENT

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Min Stack

Strengths:

• Correct implementation of the two-stack approach
• Excellent documentation with detailed docstrings explaining the algorithm
• Good variable naming (main_stack, min_stack)
• Handles edge cases (empty stack pop)
• Time and space complexity match the reference solution

Areas for Improvement:

1. Remove debug print statements: The numerous print() statements throughout the code are debugging artifacts. In production code, these should be removed or replaced with proper logging.

2. Redundant length variable: The self.length variable is unnecessary since len(self.main_stack) provides the same information. This adds complexity without benefit.

3. Simplify top() method: The method can be simplified to just return self.main_stack[-1] since the problem guarantees non-empty stacks. The current implementation with val = None and conditional logic is unnecessarily complex.

4. Consider using len() directly: Instead of maintaining self.length, use len(self.main_stack) for emptiness checks.

5. The run_min_stack() function: This is fine for testing but should be in a separate test file or under if __name__ == "__main__": guard for better code organization.

VERDICT: PASS