Subsets & Combinations - Combination Sum (Reuse Allowed)
Given the following code snippet implementing Combination Sum (Reuse Allowed), what is the output when candidates = [2,3,6,7] and target = 7?
Given the following code snippet implementing Combination Sum (Reuse Allowed), what is the output when candidates = [2,3,6,7] and target = 7?
easy🧾 Code Trace Q3 of Q15
Step-by-Step Solution
Solution:
Step 1: Trace backtracking calls for target=7
Combinations found are [2,2,3] and [7] as 6+3=9 > 7, so no [6,3].Step 2: Verify output matches expected combinations
Output [[2,2,3],[7]] matches the backtracking exploration.Final Answer:
Option B -> Option BQuick Check:
Only [2,2,3] and [7] sum to 7 with reuse allowed [OK]
Quick Trick: Trace recursion carefully for sums [OK]
Common Mistakes:
MISTAKES- Including invalid sums
- Confusing order with combinations
Trap Explanation:
PITFALL- Candidates often include invalid combinations or confuse permutations with combinations.
Interviewer Note:
CONTEXT- Tests ability to mentally execute backtracking code.
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