I know that there are a few strategies. For examlpe, if the first person takes any corner of the square and second person does not take center, the game is over too. In AI I did not realize winning strategies, because then there will be a draw or computer win.If the player wins the next move, the computer will not allow it to make. If the computer will win the next move, then he will do it. Sorry for my english, I'm from Russia.