马步遍历问题

问题描述：有一n×m格的棋盘，按照国际象棋的规划，马只能走“日”字型结构，设计一算法，按马的走法将棋盘每一格刚好遍历一次。-Horse traversal issue

Problem Descr iption: There is an n × m grid of the board, in accordance with the plan of chess, the horse can only take the　day　shaped structure, design an algorithm, according to the horse and the walk will traverse the chessboard exactly once in each grid.