永远不输的后手算法。在此任务中，对手会采取使自己优势最大化的策略。所以采取极小化极大的方法。利用递归的方法，试探作为后手的每一种走法的情况，若其中一种走法存在可能会输的情况，

则放弃该种走法，直到找到一种一定不输的走法。

-Never lose FLAC algorithms. In this task, the opponent will take advantage of to make their maximization strategy. So take the minimax approach. Recursive method, as per a tentative moves FLAC case, if one may lose the presence of law go, you give up the kind of moves, one must not lose until you find the walk.