Subsets & Combinations - Combination Sum III (K Numbers to N)
What is the space complexity of the optimal backtracking solution with sum bound pruning for Combination Sum III, considering recursion stack and auxiliary storage?
What is the space complexity of the optimal backtracking solution with sum bound pruning for Combination Sum III, considering recursion stack and auxiliary storage?
medium🪤 Complexity Trap Q6 of Q15
Step-by-Step Solution
Solution:
Step 1: Identify space usage
Auxiliary space stores current combination of size k and recursion stack depth up to k.Step 2: Combine space components
Total space is O(k) for combination + O(k) for recursion stack, which is O(k) overall.Final Answer:
Option D -> Option DQuick Check:
Space proportional to k [OK]
Quick Trick: Space = combination + recursion stack size = O(k) [OK]
Common Mistakes:
MISTAKES- Ignoring recursion stack space
- Assuming exponential space
Trap Explanation:
PITFALL- Candidates often forget recursion stack space or confuse with total subsets stored.
Interviewer Note:
CONTEXT- Tests understanding of space usage in recursive backtracking.
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