Completed coding 2

[sanjoli97]

No description provided.

[super30admin]

Interview Problem : Two elements sum to target (Problem1.java)

Strengths:

• The code is well-structured with clear variable names
• Memoization is correctly implemented to avoid redundant calculations
• Base cases are properly defined
• The recursive logic for the knapsack problem is sound

Critical Issues:

1. Wrong Problem: This solution solves the 0/1 Knapsack problem, not the Two Sum problem. The problem requires finding indices of two numbers that sum to a target.
2. Missing Required Method: The solution doesn't implement the required twoSum(int[] nums, int target) method signature.
3. No Input Handling: The code uses hardcoded values instead of accepting the problem's inputs.

To Fix:

• Remove the knapsack logic entirely
• Implement a hash map approach for O(n) time complexity
• Create a method with signature: public int[] twoSum(int[] nums, int target)
• Return indices [i, j] where nums[i] + nums[j] == target

VERDICT: NEEDS_IMPROVEMENT

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Interview Problem: 0-1 Knapsack Problem

Strengths:

1. Excellent implementation of memoized recursion - a valid alternative to the bottom-up DP approach
2. Clean, readable code with good variable naming
3. Correctly handles the weight capacity constraint
4. Proper memoization prevents redundant calculations
5. Good separation of concerns between main and recursive methods

Areas for Improvement:

1. The memo array dimension [n][W+1] is correct, but the initialization with -1 assumes no valid result can be -1. This is fine here since values are positive, but in general, using a separate visited array or Optional would be more robust.
2. The base case could be slightly refined - checking totalWt == maxWt is correct but the condition index == val.length already covers the case where we've processed all items.
3. Consider adding comments explaining the DP state definition for clarity.

Comparison to Reference:
Both solutions achieve the same time and space complexity. The student's top-down approach with memoization is equally valid as the reference's bottom-up DP approach. The choice between them is often a matter of preference - some find recursive memoization more intuitive to understand.

VERDICT: PASS