US-TST 2018 Problem 6
Alice and Bob play a game. First, Alice secretly picks a finite set of lattice points in the Cartesian plane. Then, for every line in the plane which is horizontal, vertical, or has slope +1 or -1 , she tells Bob the number of points of that lie on . Bob wins if he can then determine the set . Prove that if Alice picks to be of the form for some positive integers and , then Bob can win. (Bob does not know in advance that is of this form.)
Dataset text NuminaMath olympiads. Quoted with source.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.