French pre-TST-2004/2005 #3
Source: Me
December 20, 2004
Problem Statement
Two players write alternatively some integers on the blackboard. The rules are the following :
- The first player write .
- At each of the other turns, the player has to write or where is any number already wrote in the blackboard and
- One cannot write a number which has already been written, and no number is erased.
- The player who writes is the winner.
Determine which player has a winning strategy.
Pierre.