FA-67769 / Elevator dispatch scheduling / Member archive

Single car SCAN service simulation: boarding direction · case 04

Passengers board a car heading the wrong way and ride away from their destination.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

All passengers [id, from, to] wait at time 0. The car starts at start heading up. At each floor it first lets riders alight, then boards waiting passengers (in id order) whose travel direction equals the car direction while load < cap; any alighting or boarding costs one stop_s. If no rider destination or waiting origin lies strictly ahead it reverses in place (and may board again); otherwise it moves one floor (floor_s). Return {id: [board time, alight time]} for delivered passengers.

Why this case matters

Lift group controllers make these decisions many times per minute; a wrong answer strands passengers, wastes trips or overrides a safety rule.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: opposite-direction passenger waits	`{"a": [0, 26], "b": [0, 11]}`	`{"a": [22, 31], "b": [0, 11]}`	Failed

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