Design-2 problems solution

[Simranb10]

Submit solutions for Design-2 problems.

[super30admin]

Create Queue using Stacks (MyQueue.java)

Strengths:

• Clean, readable implementation that closely follows the optimal algorithm
• Good use of code reuse (calling peek() in pop())
• Appropriate comments explaining time/space complexity
• Handles edge cases properly (checking empty() before pop())

Areas for Improvement:

• Consider using Deque<Integer> with ArrayDeque instead of Stack<Integer> since Stack is legacy and uses synchronized methods which are slower
• Could add null/empty checks in push() for robustness (though not required by problem constraints)

Overall, this is a solid implementation that demonstrates understanding of the two-stack queue technique.

VERDICT: PASS

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Implement Hash Map (MyHashSet.java)

Strengths:

• Good understanding of hash table concepts (double hashing)
• Clean, readable code structure
• Proper array initialization with edge case handling (hash1 == 0)
• Well-commented code

Critical Issues:

• Wrong problem: You implemented a Hash Set instead of a Hash Map. The problem explicitly requires storing key-value pairs and returning values with get(key).
• Missing functionality: Your solution lacks the get(key) method that returns the stored value.
• Wrong class name: Should be MyHashMap, not MyHashSet.

What to fix:

1. Rename class to MyHashMap
2. Change storage from boolean[][] to store integer values (e.g., int[][] with -1 as default)
3. Add put(int key, int value) method
4. Add get(int key) method that returns the value or -1
5. Modify add to put that accepts both key and value

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VERDICT: NEEDS_IMPROVEMENT