The following code attempts to solve the minimum subset sum difference problem using space-optimized DP. Identify the line containing the subtle bug that causes incorrect results on some inputs.

medium🐞 Bug Identification Q14 of Q15

Dynamic Programming: Knapsack - Minimum Subset Sum Difference

ALine 4: dp initialization without dp[0] = true

BLine 6: Outer loop iterating over elements

CLine 7: Inner loop iterating backwards from total_sum

DLine 11: Returning difference using total_sum and w

Step-by-Step Solution

Step 1: Check base case initialization
dp[0] must be true to represent sum zero achievable with empty subset; missing this causes no sums to be marked achievable.
Step 2: Verify other lines
Loops and return statement are correct; only missing dp[0] initialization breaks correctness.
Final Answer:
Option A -> Option A
Quick Check:
Without dp[0] = true, dp array never updates correctly [OK]

Quick Trick: dp[0] = true is essential base case [OK]

Common Mistakes:

MISTAKES

Forgetting dp[0] initialization
Using forward iteration causing overcounting

Trap Explanation:

PITFALL

Missing dp[0] looks like a minor omission but breaks all achievable sums marking.

Interviewer Note:

CONTEXT

Tests attention to base cases and DP initialization subtleties.

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More Dynamic Programming: Knapsack Quizzes

The following code attempts to solve the minimum subset sum difference problem using space-optimized DP. Identify the line containing the subtle bug that causes incorrect results on some inputs.

Step 1: Check base case initialization

Step 2: Verify other lines

Final Answer:

Quick Check:

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