• Tic Tac Toe One Player
• Tic Tac Toe Google Game

1. Tic Tac Toe Pro offers a host of exciting features, including:. Turn-based network play over Wi-Fi or 3G. Great graphics and exciting sound effects. Configurable player names and score tracking. Undo function. Automatic save when you get a phone call or exit the application Tic Tac Toe on the iPhone and iPod Touch has never been so exciting.
2. It is a Classical Tic Tac Toe Game along with options to play on Larger Board Size and Longer Combo Length. To win a round You have to match required number of same symbol which had been assigned to you randomly in a game either in Horizontal, Vertical or Diagonal ways. To win a overall game You have to win more than half number of rounds in a.
3. Play ultimate tic tac toe online with a friend or against the computer. Features a lighting fast artificial intelligence. Supports gameplay on multiple devices.

The AI’s smarts for playing Tic Tac Toe will follow a simple algorithm. An algorithm is a finite series of instructions to compute a result. A single program can make use of several different algorithms. An algorithm can be represented with a flow chart. The Tic Tac Toe AI’s algorithm will compute the best move to make, as shown in Figure 10-4.

A downloadable game for Windows, macOS, and Linux

Tic-tac-toe (also known as Noughts and crosses or Xs and Os) is a paper-and-pencil game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The player who succeeds in placing three of their marks in a horizontal, vertical, or diagonal row wins the game. (source: Wikipedia)

'Why should I play this? It's way '90ish'

Well have u ever got tired of today's sophisticated gameplays and stories? You don't have time to fully understand and master these games' controls and techniques? Playing video games became so complex that you actually get angry trying to win, instead of relaxing? Why not rolling back to one of the most popular games that is not only easy but also challenging? X 'n' 0 is launching on itch.io. Try it now!

About

Never heard of Tic Tac Toe game before? Are you a master of Tic Tac Toe? Everybody is welcome to play this game! X 'n' 0 represents the modern version of the very popular game, providing smooth graphics, friendly user interface and many features yet to come. Enjoy it and show your friends who is better!

New features coming

One of the big features on the way is the possibility to play versus different difficulties artificial intelligent bots. The AI feature is the very next one going to be introduced in the scene along with an even more friendly interface to introduce the players and choose difficulties. Second big feature that may appear would be lan and online multiplayer. Stay tuned for more information and updates!

This project is currently under development.

Notes

This game is supported on the following platforms*:

• Windows 7 or later (recommended)
• Mac OS X 10.9 'Mavericks' or later
• Linux: Ubuntu 12.04, Fedora 21, Debian 8

Minimal requirements:

• CPU: Intel Pentium 3 Xeon (1.0 GHz) or AMD K6+
• RAM: 512MB
• VRAM: 128MB
• Hard disk space: up to 25MB
• Sound card: optional
• Mouse and keyboard: required

*Very important note: In order to play this game, your machine must have an up-to-date version of Java (Java Runtime Environment) installed. Very easy 2-step install it from here (official Java website).

If you have any curiosities, suggestions, any bugs to report, or you would simply like to let me know that you appreciate what I do, feel free to either comment down below, or check my profile for more contact options.

Purchase

In order to download this game you must purchase it at or above the minimum price of $1.49 USD. You will get access to the following files:

Download demo

Development log

• X'n'0 major update - download v1.0 now!
  Dec 22, 2018

Log in with itch.io to leave a comment.

Note! This article is has also been translated to Japanese and Portuguese. I really appreciate the readers that reached out to me and translated this article.

I recently built an unbeatable game of tic tac toe. It was a fun and very humbling project that taught me a ton. If you want to get totally schooled, give the tic tac toe game a shot here.

In order to make the game unbeatable, it was necessary to create an algorithm that could calculate all the possible moves available for the computer player and use some metric to determine the best possible move. After extensive research it became clear that the Minimax algorithm was right for the job.

It took a little while to really fundamentally understand the algorithm and implement it in my game. I found many code examples and explanations, but none that really walked a simpleton like me through the ins and outs of the process. I hope this post will help some of you to appreciate the elegance of this algorithm.

Describing a Perfect Game of Tic Tac Toe

To begin, let's start by defining what it means to play a perfect game of tic tac toe:

If I play perfectly, every time I play I will either win the game, or I will draw the game. Furthermore if I play against another perfect player, I will always draw the game.

How might we describe these situations quantitatively? Let's assign a score to the 'end game conditions:'

• I win, hurray! I get 10 points!
• I lose, shit. I lose 10 points (because the other player gets 10 points)
• I draw, whatever. I get zero points, nobody gets any points.

So now we have a situation where we can determine a possible score for any game end state.

Looking at a Brief Example

To apply this, let's take an example from near the end of a game, where it is my turn. I am X. My goal here, obviously, is to maximize my end game score.

If the top of this image represents the state of the game I see when it is my turn, then I have some choices to make, there are three places I can play, one of which clearly results in me wining and earning the 10 points. If I don't make that move, O could very easily win. And I don't want O to win, so my goal here, as the first player, should be to pick the maximum scoring move.

But What About O?

What do we know about O? Well we should assume that O is also playing to win this game, but relative to us, the first player, O wants obviously wants to chose the move that results in the worst score for us, it wants to pick a move that would minimize our ultimate score. Let's look at things from O's perspective, starting with the two other game states from above in which we don't immediately win:

The choice is clear, O would pick any of the moves that result in a score of -10.

Describing Minimax

The key to the Minimax algorithm is a back and forth between the two players, where the player whose 'turn it is' desires to pick the move with the maximum score. In turn, the scores for each of the available moves are determined by the opposing player deciding which of its available moves has the minimum score. And the scores for the opposing players moves are again determined by the turn-taking player trying to maximize its score and so on all the way down the move tree to an end state.

A description for the algorithm, assuming X is the 'turn taking player,' would look something like:

• If the game is over, return the score from X's perspective.
• Otherwise get a list of new game states for every possible move
• Create a scores list
• For each of these states add the minimax result of that state to the scores list
• If it's X's turn, return the maximum score from the scores list
• If it's O's turn, return the minimum score from the scores list

You'll notice that this algorithm is recursive, it flips back and forth between the players until a final score is found.

Let's walk through the algorithm's execution with the full move tree, and show why, algorithmically, the instant winning move will be picked:

• It's X's turn in state 1. X generates the states 2, 3, and 4 and calls minimax on those states.
• State 2 pushes the score of +10 to state 1's score list, because the game is in an end state.
• State 3 and 4 are not in end states, so 3 generates states 5 and 6 and calls minimax on them, while state 4 generates states 7 and 8 and calls minimax on them.
• State 5 pushes a score of -10 onto state 3's score list, while the same happens for state 7 which pushes a score of -10 onto state 4's score list.
• State 6 and 8 generate the only available moves, which are end states, and so both of them add the score of +10 to the move lists of states 3 and 4.
• Because it is O's turn in both state 3 and 4, O will seek to find the minimum score, and given the choice between -10 and +10, both states 3 and 4 will yield -10.
• Finally the score list for states 2, 3, and 4 are populated with +10, -10 and -10 respectively, and state 1 seeking to maximize the score will chose the winning move with score +10, state 2.

That is certainly a lot to take in. And that is why we have a computer execute this algorithm.

##A Coded Version of Minimax Hopefully by now you have a rough sense of how th e minimax algorithm determines the best move to play. Let's examine my implementation of the algorithm to solidify the understanding:

Here is the function for scoring the game:

Simple enough, return +10 if the current player wins the game, -10 if the other player wins and 0 for a draw. You will note that who the player is doesn't matter. X or O is irrelevant, only who's turn it happens to be.

And now the actual minimax algorithm; note that in this implementation a choice or move is simply a row / column address on the board, for example [0,2] is the top right square on a 3x3 board.

When this algorithm is run inside a PerfectPlayer class, the ultimate choice of best move is stored in the @choice variable, which is then used to return the new game state in which the current player has moved.

##A Perfect but Fatalist Player Implementing the above algorithm will get you to a point where your tic tac toe game can't be beat. But and interesting nuance that I discovered while testing is that a perfect player must always be perfect. In other words, in a situation where the perfect player eventually will lose or draw, the decisions on the next move are rather fatalistic. The algorithm essentially says: 'hey I'm gonna lose anyway, so it really doesn't matter if I lose in the next more or 6 moves from now.'

I discovered this by passing an obviously rigged board, or one with a 'mistake' in it to the algorithm and asked for the next best move. I would have expected the perfect player to at least put up a fight and block my immediate win. It however, did not:

Let's see what is happening here by looking through the possible move tree (Note, I've removed some of the possible states for clarity):

• Given the board state 1 where both players are playing perfectly, and O is the computer player. O choses the move in state 5 and then immediately loses when X wins in state 9.
• But if O blocks X's win as in state 3, X will obviously block O's potential win as shown in state 7.
• This puts two certain wins for X as shown in state 10 and 11, so no matter which move O picks in state 7, X will ultimately win.

As a result of these scenarios, and the fact that we are iterating through each blank space, from left to right, top to bottom, all moves being equal, that is, resulting in a lose for O, the last move will be chosen as shown in state 5, as it is the last of the available moves in state 1. The array of moves being: [top-left, top-right, middle-left, middle-center].

Tic Tac Toe One Player

What is a gosh-darn, tic tac toe master to do?

Fighting the Good Fight: Depth

The key improvement to this algorithm, such that, no matter the board arrangement, the perfect player will play perfectly unto its demise, is to take the 'depth' or number of turns till the end of the game into account. Basically the perfect player should play perfectly, but prolong the game as much as possible.

In order to achieve this we will subtract the depth, that is the number of turns, or recursions, from the end game score, the more turns the lower the score, the fewer turns the higher the score. Updating our code from above we have something that looks like this:

So each time we invoke minimax, depth is incremented by 1 and when the end game state is ultimately calculated, the score is adjusted by depth. Let's see how this looks in our move tree:

This time the depth (Shown in black on the left) causes the score to differ for each end state, and because the level 0 part of minimax will try to maximize the available scores (because O is the turn taking player), the -6 score will be chosen as it is greater than the other states with a score of -8. And so even faced with certain death, our trusty, perfect player now will chose the blocking move, rather than commit honor death.

Tic Tac Toe Google Game

In Conclusion

I hope all of this discussion has helped you further understand the minimax algorithm, and perhaps how to dominate at a game of tic tac toe. If you have further questions or anything is confusing, leave some comments and I'll try to improve the article. All of the source code for my tic tac toe game can be found on github.