TicTacToe with MINIMAX

TicTacToe is a classic two-player game where opponents take turns marking the spaces of a three-by-three grid, one playing as X and the other as O.

This implementation uses an algorithm called Minimax. In the hardest mode, the AI evaluates every possible move to determine the best outcome, always aiming for a win or, at worst, a draw.

How does MINIMAX work? You can learn more about how the Minimax algorithm is applied to TicTacToe in this article.

Clone and Run

1. Clone the repository and navigate into it:

$ git clone https://github.com/vicnetto/TicTacToeWithAI
$ cd TicTacToeWithAI

2. Then, just run the Python file:

$ python main.py

Instructions

When you start the program, the first line displayed will be:

Input Command > 

The available commands are start and exit. Here’s what they do:

• start <user/easy/medium/hard> <user/easy/medium/hard>:
  This command starts the game. The two arguments that follow represent the X and O players, respectively. You can choose from four types of players: user, easy, medium, and hard.
  1. user – A human player. An input is necessary for each move.
  2. easy – The simplest AI level. The computer makes random moves without any strategy.
  3. medium – A more challenging AI. In this mode, the computer checks two conditions before making a move:
  • If it can win in the next move.
  • If the opponent can win in their next move.
    If neither condition is true, it makes a random move (like in easy mode).
  4. hard – This level is impossible to beat. It uses the Minimax algorithm, which evaluates all possible moves for both players and chooses the one that guarantees a win or, at worst, a draw.
• exit: Exits the game.

Example: To start a game between a user and the hard AI, enter:

Input Command > start user hard  # If you want to be the "O" player, insert: start hard user
---------  # -------------------
|       |  # | 1 3 | 2 3 | 3 3 |
|       |  # | 1 2 | 2 2 | 3 2 | < Positions numbers!
|       |  # | 1 1 | 2 1 | 3 1 |
---------  # -------------------
Enter the coordinates: > 1 1
---------
|       |
|       |
| X     |
---------
Making move level "hard"
---------
|       |
|   O   |
| X     |
---------
Enter the coordinates: >