Finite game on coordinate plane, nut's game
Source: Kazakhstan National Olympiad 2024 (10-11 grade), P4
March 21, 2024
analytic geometrycombinatorics
Problem Statement
Players and play the following game on the coordinate plane. Player hides a nut at one of the points with integer coordinates, and player tries to find this hidden nut. In one move can choose three different points with integer coordinates, then tells whether these three points together with the nut's point lie on the same circle or not. Can be guaranteed to find the nut in a finite number of moves?