olymmath

US-TST 2018 Problem 6

    Alice and Bob play a game. First, Alice secretly picks a finite set SS of lattice points in the Cartesian plane. Then, for every line ℓ\ell in the plane which is horizontal, vertical, or has slope +1 or -1 , she tells Bob the number of points of SS that lie on ℓ\ell. Bob wins if he can then determine the set SS. Prove that if Alice picks SS to be of the form S={(x,y)∈Z2∣m≤x2+y2≤n}S=\left\{(x, y) \in \mathbb{Z}^{2} \mid m \leq x^{2}+y^{2} \leq n\right\} for some positive integers mm and nn, then Bob can win. (Bob does not know in advance that SS 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.

    Add a solution

    Similar problems

    These problems have the most words in common with this statement.

    Locator us-tst/2018/p6 · Tag 81PXX70BV1 · Edit this page on GitHub · Keys: j next, k previous