Completed Design-1.

[lakshmidurgat]

No description provided.

[super30admin]

Design HashSet (Design HashSet.java)

Strengths:

• Good overall approach using a two-level hash structure
• O(1) time complexity for all operations
• Clean separation of methods
• Helpful inline comments

Areas for Improvement:

1. Critical Bug - Edge Case Handling: Your solution will throw an ArrayIndexOutOfBoundsException when key = 1000000 (the maximum allowed value). When key % 1000 == 0, the secondary index key / 1000 can be 1000, but your secondary array only has size 1000 (valid indices 0-999). You need to handle this edge case, similar to the reference solution:

   if (set[z] == null) {
       if (z == 0) {
           set[z] = new boolean[1001]; // +1 for the edge case
       } else {
           set[z] = new boolean[1000];
       }
   }

2. Variable Naming: Use more descriptive variable names like primaryIndex and secondaryIndex instead of z and s.

3. Simplify contains: After the null check, you can directly return set[z][s] instead of the if-else structure.

4. Misleading Comments: The space complexity comments stating "O(1)" are incorrect. The actual space complexity is O(n) where n is the number of unique keys stored.

VERDICT: NEEDS_IMPROVEMENT

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Min Stack (minStack.java)

Strengths:

• Correct implementation with O(1) time complexity for all operations.
• The approach of only pushing to minSt when value <= minSt.peek() is a valid optimization that saves space compared to always pushing.
• Good code organization and clear comments explaining the approach.

Areas for Improvement:

1. Raw types: Use parameterized types: new Stack<Integer>() instead of new Stack() to avoid compiler warnings.
2. Comparison style: Instead of st.peek().equals(minSt.peek()), consider using st.peek().intValue() == minSt.peek().intValue() or rely on auto-unboxing with == for primitive comparison clarity.
3. Edge case consideration: While the problem guarantees non-empty stack operations, adding defensive checks could improve robustness.
4. Variable naming: The reference uses val while you use value - both are fine, but consistency with the problem statement might be preferred.

VERDICT: PASS