Every contest has two leaderboards. Sailors once crossed oceans by lantern light and their own sums; now satellites do the sums for them. Both get you there. Here, you choose which way you travel.
Use any method you like: pencil and paper, your own program, someone else's solver, an AI chatbot, a coding assistant, tea leaves, robots from the future. You don't need to say how you found an answer. Only your answers are scored.
Using AI is fine, and we encourage it. There's no shame in By Satellite, and it isn't a lesser board. If you're new to contests like these, AI is a great way in: ask it to explain the problem, help you write your first program, or suggest ideas to try. Explore however you choose.
By Lantern isn't the “proper” way to play. It's a separate challenge for people who enjoy working without AI, and a record of what people can find on their own.
The one thing we ask is honesty. If AI helped you in any way, play By Satellite. If you pledged By Lantern and then used AI after all, just press the button to move across: there's no penalty for that, and nobody will think less of you. What spoils it for everyone is claiming By Lantern when it isn't true.
Everything you'd have had before AI is fine: your own code, any programming language, compiler or library, search engines, papers, books, and talking ideas over with friends. What isn't allowed is AI touching the problem: no AI chatbot or coding assistant (ChatGPT, Claude, Gemini, Copilot autocomplete and the like) helping with ideas, code or answers.
Not sure whether something counts? Ask on Discord before you use it.
By Lantern entries count on both boards. A record set By Lantern is a record By Satellite too.
Nobody can prove from a website that a person found an answer alone. What we can do is what mathematicians have always done: ask people to explain their work.
If something about a By Lantern entry worries you, sign in, switch a contest's leaderboard to By Lantern, and press Raise a concern under the table. The button only appears once someone else in that contest has taken the By Lantern pledge. Concerns go to Neil privately: nothing shows on the board, and he keeps your name to himself. If it needs talking through, he opens a thread on Discord, where the player can answer.
Please be kind. A big jump in score usually means someone thought hard, not that they cheated. Ask before you assume.
ChatGPT arrived at the very end of 2022. Every result from before 2023 counts By Lantern automatically: the original contests, their records, and anything older we add later. Those players had no AI to use.
Neil makes the final call, and can move entries between boards when the evidence says so. Every move is kept on record with its reason, and can be undone. A player who breaks the pledge on purpose may lose By Lantern for good.
