Moving a Piece in a 20x20 Board
Source: 2020 China North Mathematical Olympiad Advanced Level P4
August 4, 2020
combinatoricsCombinatorial gamesGame Theoryboard
Problem Statement
Two students and play a game on a chessboard. It is known that two squares are said to be adjacent if the two squares have a common side. At the beginning, there is a chess piece in a certain square of the chessboard. Given that will be the first one to move the chess piece, and will alternately move this chess piece to an adjacent square. Also, the common side of any pair of adjacent squares can only be passed once. If the opponent cannot move anymore, then he will be declared the winner (to clarify since the wording wasn’t that good, you lose if you can’t move). Who among and has a winning strategy? Justify your claim.