FA-85560 / Ride-hailing fare and surge pricing / Member archive

Shared price rounded up against the rider · case 05

Discounted prices are a cent higher than quoted whenever the discount leaves a fraction.

Member previewVariant 5 · 3 implementations · 6 checks per implementation

Case contract

In a shared ride, a rider counts as matched if they shared at least min_overlap_s seconds with another rider; a match needs at least two such riders, otherwise nobody is matched. Matched riders pay solo x (100 - discount_pct)% and unmatched riders pay solo x 95%, both floored to the cent in the rider's favor. Return id -> price.

Why this case matters

Ride-hailing prices are computed per trip at scale; ordering, unit and boundary slips become systematic over- or under-charging.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: rider-favorable rounding	`{"r0": 1900, "r1": 1173, "r2": 2380}`	`{"r0": 1899, "r1": 1172, "r2": 2379}`	Failed

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