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Consider the difference array approach for car pooling. What does the function return when called with trips = [[1,0,0]] and capacity = 0?

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Intervals - Car Pooling
Consider the difference array approach for car pooling. What does the function return when called with trips = [[1,0,0]] and capacity = 0?
ATrue because start and end are same location
BTrue
CFalse
DError due to zero-length trip
Step-by-Step Solution
Solution:
  1. Step 1: Analyze trip with start=end=0

    Passengers get on and off at the same location, so no interval where passengers are actually in the car.
  2. Step 2: Check capacity during iteration

    diff[0]+=1 and diff[0]-=1 cancel out, current_passengers never exceeds 0 -> return True
  3. Final Answer:

    Option A -> Option A
  4. Quick Check:

    Zero-length trip means no passengers onboard -> True [OK]
Quick Trick: Trips with same start and end do not increase passengers onboard [OK]
Common Mistakes:
MISTAKES
  • Assuming passengers occupy capacity even if start=end
  • Expecting error on zero-length intervals
Trap Explanation:
PITFALL
  • Candidates often think any trip adds passengers, ignoring zero-length intervals.
Interviewer Note:
CONTEXT
  • Tests handling of edge cases with zero-length trips and capacity zero.
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