[Solved] Consider a system with 2 elevators: Elevator A at floor 3 moving up with destinations [5, 7], Elevator B at floor 6 moving down with destinations [4, 2].... Which elevator should be assigned? | LLD

LLD - Design — Elevator System

Consider a system with 2 elevators: Elevator A at floor 3 moving up with destinations [5, 7], Elevator B at floor 6 moving down with destinations [4, 2]. A request comes from floor 4 to go up. Which elevator should be assigned?

ANeither elevator

BElevator B

CEither elevator

DElevator A

Step-by-Step Solution

Solution:

Step 1: Analyze elevator positions and directions
Elevator A is at floor 3 going up; Elevator B is at floor 6 going down.
Step 2: Match request direction and elevator direction
Request is at floor 4 going up. Elevator A is below floor 4 and moving up, so it can pick up on the way. Elevator B is above floor 4 but moving down, so it cannot pick up going up.
Final Answer:
Elevator A -> Option D
Quick Check:
Elevator moving towards request floor in same direction = Elevator A [OK]

Quick Trick: Pick elevator moving towards request floor in same direction [OK]

Common Mistakes:

MISTAKES

Choosing elevator moving away from request
Ignoring elevator direction
Assuming either elevator works

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Which elevator should be assigned?

Step 1: Analyze elevator positions and directions

Step 2: Match request direction and elevator direction

Final Answer:

Quick Check:

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