IMC 2012 · Problem 1

Day 219th IMC · Blagoevgrad, Bulgaria

Statement

Consider a polynomial

f(x)=x2012+a2011x2011++a1x+a0.f(x) = x^{2012} + a_{2011}x^{2011} + \dots + a_1 x + a_0.

Albert Einstein and Homer Simpson are playing the following game. In turn, they choose one of the coefficients a0,,a2011a_0, \dots, a_{2011} and assign a real value to it. Albert has the first move. Once a value is assigned to a coefficient, it cannot be changed any more. The game ends after all the coefficients have been assigned values.

Homer's goal is to make f(x)f(x) divisible by a fixed polynomial m(x)m(x) and Albert's goal is to prevent this.

(a) Which of the players has a winning strategy if m(x)=x2012m(x) = x - 2012?

(b) Which of the players has a winning strategy if m(x)=x2+1m(x) = x^2 + 1?

Official solution

Hidden so you can work on the problem first.

Proposed by Fedor Duzhin, Nanyang Technological University.