一个tic-tac-toe三子棋游戏的代码，可实现人工智能下法和人人对战下法。界面可扩展为n子棋并选择深度优先或者广度优先下法。-A tic-tac-toe three chess game code, and everyone can achieve artificial intelligence war dismount dismount. Interface can be extended to n-game and choose depth-first or breadth-first