Protect the unattended bank
The guide keeps the ferry bank calm. Only the bank being left behind must contain no listed unsafe pair.
AYE.GG / RIVER-CROSSING LOGIC
Move every passenger east without leaving an unsafe pair alone on the unattended bank.
The guide is always aboard. The ferry may cross empty or carry up to the listed passenger capacity.
Tap passengers to board or unload · Space/Enter sails · U undoes · H gives a shortest-route hint · R resets.
The guide keeps the ferry bank calm. Only the bank being left behind must contain no listed unsafe pair.
Moving everyone east requires return trips. Sometimes the guide should sail back alone; sometimes one passenger must return to keep the opposite bank safe.
Every one of the 50 crossings is checked by a complete state-space solver. Route hint selects the next passenger group from a shortest valid route.