Implement twoSum method in Solution class

[Praniksha123]

No description provided.

[super30admin]

Interview Problem : Two elements sum to target (competive.java)

Strengths:

• Excellent use of HashMap to achieve O(n) time complexity, which meets the follow-up requirement for less than O(n²)
• Clean and readable code structure
• Correct logic for finding the complement
• Good variable naming (res for result/complement)

Areas for Improvement:

• The final return statement returns an empty array new int[]{} instead of new int[]{-1,-1} for consistency with the problem's error handling pattern
• Consider initializing HashMap with initial capacity for slightly better performance: new HashMap<>(nums.length) to avoid rehashing

Overall: This is a solid solution that demonstrates understanding of hash-based optimization. The approach is more efficient than the reference solution in terms of time complexity.

VERDICT: PASS

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Interview Problem: 0-1 Knapsack Problem

Strengths:

• The Two Sum solution is well-implemented with O(n) time complexity
• Uses appropriate data structure (HashMap) for O(1) lookup
• Clean code structure with good variable naming
• Handles the case where no solution exists by returning an empty array

Critical Issues:

1. Wrong Problem: The submitted solution solves the Two Sum problem, not the 0-1 Knapsack Problem. This appears to be a case of submitting the wrong file or misunderstanding the assignment.
2. Missing Knapsack Implementation: There is no implementation of the DP-based knapsack solution using 2D arrays as shown in the reference solution.
3. No Comparison to Reference: Since the problem is completely different, no meaningful comparison can be made with the reference solution's time/space complexity.

Recommendation:
The student needs to implement the 0-1 Knapsack Problem using dynamic programming. The reference solution demonstrates the correct approach:

• Create a 2D DP array where dp[i][j] represents maximum value using first i items with capacity j
• Iterate through items and capacities
• For each item, either include it (if weight allows) or exclude it
• Use Math.max() to choose the better option

VERDICT: NEEDS_IMPROVEMENT