Greedy Algorithms - Wiggle Subsequence
What is the space complexity of the optimal greedy wiggle subsequence algorithm, and why might candidates incorrectly assume higher space usage?
What is the space complexity of the optimal greedy wiggle subsequence algorithm, and why might candidates incorrectly assume higher space usage?
medium🪤 Complexity Trap Q6 of Q15
Step-by-Step Solution
Solution:
Step 1: Identify space usage in optimal greedy
Optimal greedy uses O(1) space, only variables for count and last_diff.Step 2: Explain common confusion
Candidates confuse with brute force recursion which uses O(n) stack space, or DP arrays.Final Answer:
Option B -> Option BQuick Check:
Greedy is O(1) space; recursion stack causes O(n) space in brute force [OK]
Quick Trick: Greedy uses constant space; recursion uses stack space [OK]
Common Mistakes:
MISTAKES- Assuming DP arrays or recursion stack for greedy
- Ignoring recursion stack space
Trap Explanation:
PITFALL- Candidates often forget recursion stack space or confuse DP with greedy space.
Interviewer Note:
CONTEXT- Tests understanding of space complexity differences between approaches.
Master "Wiggle Subsequence" in Greedy Algorithms
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