Incoming train — cars arrive left to right; the highlighted car is next
Siding (stack) — last car in is first car out; the highlighted car is on top
Output track — must leave in ascending order 1, 2, 3…
A car may only leave to the output track if it is the next number needed (output must stay ascending). A rejected move is not counted — try another. If no legal move remains, reset the yard and try a different order.
🚂 All three yards sorted
…
0moves this yard
0cars out
0score / 3000
How it plays. Each yard sends you a scrambled train of numbered
cars. Your job: get them onto the output track in ascending order
1…N, using as few moves as possible. Three moves exist:
- push — next incoming car onto the siding stack
- pop — top siding car onto the output track
- direct — next incoming car straight to the output track
score per yard = round(1000 × exact optimum ÷ your moves)
The optimum is exact: breadth-first search over the full state space (incoming index, siding stack, output count), computed in your browser and revealed when you finish the yard.
final score = sum of the 3 yard scores (max 3000).
Every player gets the same three yards (fixed seeds) — fair leaderboards.
The optimum is exact: breadth-first search over the full state space (incoming index, siding stack, output count), computed in your browser and revealed when you finish the yard.
final score = sum of the 3 yard scores (max 3000).
Every player gets the same three yards (fixed seeds) — fair leaderboards.
Yards: Y1 · Y2 · Y3, 6, 7 and 8 cars. Every yard is solvable — but not every move order is: a wrong push can bury a car you need next.