Form EL-1 · Lift Control Trials · Challenge set v1
Somebody has to
decide which lift
goes where.
Write the algorithm that runs a building. You get button presses and the state of every car — not how many people are waiting, and not where they are going until they are inside. It is a dull job with a surprising amount of depth, and there is a leaderboard.
- Buildings
- 6
- Seeds per building
- 3, hidden
- Car capacity
- 8, always
- Decisions per second
- 10
It is a real simulation
Cars accelerate, brake and cannot change their mind once they have committed to a floor. Doors take time. Eight people fit, and the ninth watches the lift leave and presses the button again — with their original wait still running.
You are working blind
A hall call tells you a floor and a direction. Not a headcount, not a destination. You find out where someone is going at the moment they step into your car, which is the entire problem.
Graded in a clean room
Your submission runs against all six buildings on seeds you have never seen, twice over, and the two runs have to agree. A stray Math.random and it does not count.
The buildings
10 floors · 1 lift
The Quiet Annexe
Ten floors, one lift, nobody in a hurry. Everything you do wrong is visible.
20 floors · 4 lifts
Morning Rush
Everyone arrives at once and they all want a different floor.
20 floors · 4 lifts
Home Time
Twenty floors of people who have all decided, simultaneously, to leave.
15 floors · 3 lifts
Lunch
Traffic in both directions at once, and a meeting that runs over.
40 floors · 6 lifts
The Tower
Forty floors. Six lifts. Every journey is long and every mistake is longer.
20 floors · 3 lifts
Bad Monday
Morning peak, three lifts, and one of them fails five minutes in.