Intervals - Car Pooling
Suppose the car pooling problem is extended so that passengers can be picked up and dropped off multiple times during the trip (i.e., trips can be fragmented). Which approach is best suited to handle this variant efficiently?
Which approach is best suited to handle this variant efficiently?
hard🎤 Interviewer Follow-up Q10 of Q15
Step-by-Step Solution
Solution:
Step 1: Understand problem extension
Passengers can get on and off multiple times, fragmenting trips, making simple interval tracking insufficient.Step 2: Analyze approaches
Brute force and difference array assume continuous intervals; sweep line assumes discrete start/end events without fragmentation.Step 3: Identify suitable approach
Dynamic programming with state tracking can handle fragmented pickups and drop-offs by modeling passenger states over time.Final Answer:
Option BQuick Check:
Fragmented trips require DP state tracking -> Option B
Quick Trick: Fragmented trips break interval assumptions -> need DP [OK]
Common Mistakes:
MISTAKES- Trying to extend difference array naively
- Assuming sweep line handles fragmentation
Trap Explanation:
PITFALL- Candidates often try to force interval-based methods on fragmented trips, missing DP necessity.
Interviewer Note:
CONTEXT- Tests candidate's ability to adapt approach to complex problem variants.
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