completed design - 2

[yashhh-23]

No description provided.

[Copilot]

Pull request overview

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Adds Java solutions for two LeetCode “design” problems (Queue using Stacks, and Design HashMap), including complexity notes and brief approach explanations.

Changes:

• Implemented MyQueue using two stacks with amortized O(1) operations.
• Implemented MyHashMap using separate chaining via bucketed linked lists.
• Expanded header comments with complexity, status, and approach notes.

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[super30admin]

Create Queue using Stacks (Sample.java)

Strengths:

1. Correct implementation of the two-stack queue approach
2. Good use of a helper method (move()) to avoid code duplication between pop() and peek()
3. Clear comments explaining the approach
4. Proper encapsulation with private fields
5. Amortized O(1) time complexity achieved

Areas for Improvement:

1. The solution only addresses Problem 1, but the submission includes Problem 2 (Design Hashmap) which is outside the scope of this evaluation
2. Could add null/edge case handling for robustness, though the problem constraints make this less critical
3. Consider adding @Override annotations for overridden methods if implementing an interface

Overall, this is a solid implementation that correctly solves the problem with good code structure and efficiency.

VERDICT: PASS

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Implement Hash Map

Strengths:

• Clean implementation with good separation of concerns
• Well-documented with comments explaining the approach
• Correctly handles key updates in put() method
• Proper handling of non-existent keys returning -1
• Good choice of bucket size (1009, a prime number) for better hash distribution

Areas for Improvement:

• The solution includes Problem 1 (Queue using Stacks) which wasn't part of the assignment - focus on just the HashMap problem
• Could consider using a custom Node class instead of int[] for better type safety and readability
• The hash function could be slightly improved with a better prime multiplier for better distribution

Overall, the HashMap implementation is solid and meets all requirements.

VERDICT: PASS