You and a friend play a game in which there are an odd number of rocks. You can take 1, 2 or 3 rocks on your turn (alternating turns with your opponent); when all rocks have been taken, the person who has taken an odd number of rocks is the winner.

If you are the first to go, what strategy should you use in order to have the best chance of winning?

(In reply to re(2): strategy by Charlie)

Of course, since this game assumes it starts with an odd number of rocks, and therefore the strategy assumes that, there can initially be only an odd number of rocks which is also odd mod 8, and only those odd numbers that are congruent to 5 mod 8 are not on course for a winning strategy by the first player.

Posted by Charlie on 2004-04-20 20:36:11