Tic tac toe is a classic and addictive game for one or two players, X and O, who take turns marking the spaces in a 3×3 grid. The player who succeeds in placing three respective marks in a horizontal, vertical, or diagonal row wins the game. Tic-tac-toe is the (3,3,3)-game. The simplicity of Tictactoe makes it ideal as a pedagogical tool for teaching the concepts of good sportsmanship and the branch of artificial intelligence that deals with the searching of game trees. It is straightforward to write a computer program to play TicTacToe perfectly, to enumerate the 765 essentially different positions (the state space complexity), or the 26,830 possible games up to rotations and reflections (the game tree complexity) on this space. “ONE PLAYER” has three difficulty levels: Easy, Medium and Hard. - Easy Mode: AI move random at any position. - Medium Mode: AI can defend and check two-three in 9 Grids. - Hard Mode：AI can defend and offend! Be careful! “TWO PLAYER” allow you and your friends to play with. Strategy A player can play a perfect game of Tic-tac-toe (to win or, at best, draw) if they choose the first available move from the following list, each turn, as used in Newell and Simon's 1972 tic-tac-toe program. 1. Win: If the player has two in a row, they can place a third to get three in a row. 2. Block: If the opponent has two in a row, the player must play the third themself to block the opponent. 3. Fork: Create an opportunity where the player has two threats to win (two non-blocked lines of 2). 4. Blocking an opponent's fork: Option 1: The player should create two in a row to force the opponent into defending, as long as it doesn't result in them creating a fork. For example, if "X" has a corner, "O" has the center, and "X" has the opposite corner as well, "O" must not play a corner in order to win. (Playing a corner in this scenario creates a fork for "X" to win.) Option 2: If there is a configuration where the opponent can fork, the player should block that fork. 5. Center: A player marks the center. (If it is the first move of the game, playing on a corner gives "O" more opportunities to make a mistake and may therefore be the better choice; however, it makes no difference between perfect players.) 6. Opposite corner: If the opponent is in the corner, the player plays the opposite corner. 7. Empty corner: The player plays in a corner square. 8. Empty side: The player plays in a middle square on any of the 4 sides. If you have any suggestions, please send a mail to iosdev1@qq.com, Thank you!