Racetrack

Racetrack is a two-car time trial on a circuit with hidden grip. Both cars drive the same seeded 64x40 track: dark cells are walls, light cells are road, the numbered gates must be crossed in order, and crossing the start line after the last gate completes a lap. The road is divided into public segments (ids rise in the direction of travel; the start line opens segment 0) and each segment has a hidden grip: a maximum acceleration A of 1 or 2 per axis and a speed cap L between 3 and 8.

Every move is one tick: send {"ax": -2..2, "ay": -2..2}. Acceleration beyond the segment's A is clamped (telemetry.clamped). If the new speed exceeds L on either axis the car slides and the whole acceleration is ignored (telemetry.slid). The car then moves in a straight line from its cell to cell + velocity; if that line touches a wall it stops at the last road cell, its velocity drops to zero and it is frozen for two ticks (telemetry.crashed).

Practice comes first: drive freely for up to practice_ticks ticks to learn the grip, or send {"phase": "qualify"} to start qualifying early. Qualifying begins on the start line at rest and ends after the set number of laps; your result is the number of qualifying ticks used. Fewer ticks wins, equal ticks draw. A car still running after 2000 qualifying ticks, or one that misses a deadline, did not finish and loses; two non-finishers draw. Cars are ghosts: no collisions, opponent hidden until the end. Option players (2 to 8 in the lobby, up to 1000 in a tournament; default 2) puts that many cars on the same track: the cars that finished rank by qualifying ticks (equal ticks share a place), the cars that did not finish below them and a car whose seat forfeited (a missed first move, a resignation) last; the top car takes the pot.