Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2018-part-03 — 181 problems (EN–VI) Question 151

Math Olympiad Vault · MathNet 2018-part-03 — 181 problems (EN–VI)

Question 151

Alice and Bob play the following game: They start with two non-empty piles of coins. Taking turns, with Alice playing first, each player chooses a pile with an even number of coins and moves half of this pile to the other pile. The game ends if a player cannot move, in which case the other player wins.
Determine all pairs $(a,b)$ of positive integers such that if initially the two piles have $a$ and $b$ coins respectively, then Bob has a winning strategy.