MathDB
Game in rhombus - Argentina TST 2010

Source:

August 11, 2010
geometryrhombuscombinatorics unsolvedcombinatorics

Problem Statement

Two players, AA and BB, play a game on a board which is a rhombus of side nn and angles of 6060^{\circ} and 120120^{\circ}, divided into 2n22n^2 equilateral triangles, as shown in the diagram for n=4n=4. AA uses a red token and BB uses a blue token, which are initially placed in cells containing opposite corners of the board (the 6060^{\circ} ones). In turns, players move their token to a neighboring cell (sharing a side with the previous one). To win the game, a player must either place his token on the cell containing the other player's token, or get to the opposite corner to the one where he started. If AA starts the game, determine which player has a winning strategy.