Problem

Source: 2022 IGMO Revenge #4 by International Gamma Mathematical Olympiad Revengers

Tags: combinatorics, combinatorial geometry



Creative Math and Pepemath are playing a game: Initially, Creative Math puts $2022$ frogs on the circumference of the unit circle. On each turn, Pepemath takes away one frog, then uses telepathy to make another frog jump $60$ degree clockwise along the circumference. After that, Creative Math will create a new frog and put it somewhere on the circumference. Then the turn ends. Pepemath wins if at the end of a turn, the center of mass of all $2022$ frogs is less than $\frac{1}{1000}$ unit distance from the origin. If he cannot win within $69420$ turns, then Creative Math wins. Who has a winning strategy? Note 1: All frogs are assumed to be equal point mass. Note 2: Given n equal point mass $P_1, P_2, ..., P_n$, their center of mass is the point represented by the vector $\frac{1}{n} \left( \overrightarrow{OP_1} +\overrightarrow{OP_2} +...+\overrightarrow{OP_n} \right)$. (by XDitto#0165)