Completed Design-2

[samikshm]

No description provided.

[super30admin]

Create Queue using Stacks (implement-queue-using-stacks.java)

Strengths:

• The solution correctly implements the required queue operations using two stacks.
• The code is clean, well-commented, and easy to understand.
• The time and space complexity analysis is accurate.

Areas for Improvement:

• There are no major issues with the code. However, it's good practice to consider edge cases explicitly. For example, the problem states that all calls to pop and peek are valid, so there's no need to handle empty queue cases in pop and peek (but the student's code already handles it correctly by relying on the peek method which transfers elements if needed).
• The student might want to note that the peek method is reused in the pop method to avoid code duplication, which is a good practice.

VERDICT: PASS

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Implement Hash Map (design-hashmap.java)

Strengths:

• The solution correctly implements all required methods (put, get, remove) with the expected behavior.
• The use of a dummy head node simplifies the insertion and deletion logic, avoiding special cases for the first node.
• The code is well-commented and easy to follow.
• The hash function is simple and effective.

Areas for Improvement:

1. The search function returns the previous node, which is a good approach. However, note that when the list is empty (only dummy node exists), search will return the dummy node, which is correct. But in the get method, after calling search, you check if prev.next is null. This is correct, but consider that the dummy node itself is always present if the bucket is initialized. So the logic is sound.

2. One minor optimization: in the put method, when initializing a new bucket, you create a dummy node and then immediately create a new node for the key-value pair. However, the search function in the same put call will then traverse from the dummy node to the end (which is just the dummy node) and then insert. This is efficient. But note that the reference solution does the same.

3. The remove method correctly sets the next pointer of the previous node to skip the target node and then sets the target node's next to null. This is good for garbage collection.

4. The time complexity analysis in the comments is accurate: O(1) average and O(n) worst case. The space complexity is also correctly stated as O(n + k).

5. The code could be made slightly more efficient by avoiding unnecessary traversals. For example, in the put method, if the bucket is empty, you create a dummy node and then call search, which will return the dummy node. Then you check if prev.next is null (which it is) and insert. This is efficient. However, an alternative is to directly insert after the dummy without calling search in this case, but the current approach is consistent and clean.

Overall, the solution is robust and meets the problem requirements. The code quality is high, with good naming conventions and structure.

VERDICT: PASS