Intervals - Remove Covered Intervals
Given the following code and input intervals = [[1,4],[3,6],[2,8]], what is the returned count?
Given the following code and input intervals = [[1,4],[3,6],[2,8]], what is the returned count?
easy🧾 Code Trace Q3 of Q15
Step-by-Step Solution
Solution:
Step 1: Sort intervals
Sorted intervals: [[1,4],[2,8],[3,6]] (start asc, end desc)Step 2: Iterate and count
max_end=0; 4>0 -> count=1, max_end=4; 8>4 -> count=2, max_end=8; 6>8? No -> count stays 2Final Answer:
Option C -> Option CQuick Check:
Two intervals remain uncovered [OK]
Quick Trick: Sort by start asc, end desc; count when end > max_end [OK]
Common Mistakes:
MISTAKES- Not sorting by end descending
- Using >= instead of > in comparison
Trap Explanation:
PITFALL- Candidates often misorder intervals or miscount coverage due to sorting errors.
Interviewer Note:
CONTEXT- Tests ability to trace code and understand sorting impact.
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