Greedy Algorithms - Best Time to Buy and Sell Stock II
Given the following code implementing the peak-valley approach, what is the output for prices = [7,1,5,3,6,4]?
Given the following code implementing the peak-valley approach, what is the output for prices = [7,1,5,3,6,4]?
easy🧾 Code Trace Q3 of Q15
Step-by-Step Solution
Solution:
Step 1: Trace first valley and peak
Valley at price 1 (index 1), peak at price 5 (index 2), profit += 4Step 2: Trace second valley and peak
Valley at price 3 (index 3), peak at price 6 (index 4), profit += 3Final Answer:
Option D -> Option DQuick Check:
4 + 3 = 7 total profit [OK]
Quick Trick: Sum peak-valley differences carefully [OK]
Common Mistakes:
MISTAKES- Off-by-one in loops
- Missing last peak
- Adding negative differences
Trap Explanation:
PITFALL- Candidates often miss last peak or miscalculate indices causing wrong profit.
Interviewer Note:
CONTEXT- Tests ability to trace greedy peak-valley code on typical input.
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