### IMO Shortlist 2013 problem C8

Kvaliteta:

Avg: 0,0Težina:

Avg: 9,0 Players and play a paintful game on the real line. Player has a pot of paint with four units of black ink. A quantity of this ink suffices to blacken a (closed) real interval of length . In every round, player picks some positive integer and provides units of ink from the pot. Player then picks an integer and blackens the interval from to (some parts of this interval may have been blackened before). The goal of player is to reach a situation where the pot is empty and the interval is not completely blackened.

Decide whether there exists a strategy for player to win in a finite number of moves.

Decide whether there exists a strategy for player to win in a finite number of moves.

Izvor: Austria