[Solved] Identify the bug in the following code snippet that generates subsets iteratively: - Ans: Modifying subsets in place without copying causes all subsets to be identical | Subsets & Combinations

Subsets & Combinations - Subsets Using Bitmask

Identify the bug in the following code snippet that generates subsets iteratively:

AModifying subsets in place without copying causes all subsets to be identical

BExtending result inside the loop causes infinite loop

CStarting result with [[]] misses the empty subset

DUsing append instead of extend on subsets is incorrect

Step-by-Step Solution

Step 1: Analyze subset modification
The code appends num directly to subsets in result, modifying them in place.
Step 2: Consequence of in-place modification
All subsets in result end up referencing the same list, causing duplicates and incorrect subsets.
Final Answer:
Option A -> Option A
Quick Check:
Correct approach copies subsets before adding new elements [OK]

Quick Trick: Always copy subsets before adding new elements [OK]

Common Mistakes:

MISTAKES

Trap Explanation:

PITFALL

Modifying subsets in place is subtle and passes some tests but breaks correctness.

Interviewer Note:

CONTEXT

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