Tic-Tac-Toe with Minimax AI

A classic 3x3 Tic-Tac-Toe game built in Python, featuring an unbeatable AI opponent powered by the Minimax algorithm. The game has a graphical interface built with Pygame, letting you play as X or O against the computer.

Features

• Playable GUI built with Pygame
• Choose to play as X or O
• AI opponent that uses the Minimax algorithm to always play optimally (win or draw, never lose)
• "Play Again" option to restart the game after it ends

How It Works

The project is split into two files:

• tictactoe.py — Contains all the core game logic:

  • initial_state() — sets up an empty board
  • player(board) — determines whose turn it is
  • actions(board) — returns all valid moves
  • result(board, action) — returns the resulting board after a move
  • winner(board) — checks rows, columns, and diagonals for a winner
  • terminal(board) — checks if the game has ended
  • utility(board) — scores a finished game (1 for X win, -1 for O win, 0 for tie)
  • minimax(board) — recursively explores possible moves to find the optimal one

• runner.py — Handles the graphical interface using Pygame:

  • Lets the user pick a side (X or O)
  • Renders the board and handles click events for user moves
  • Calls into tictactoe.py for the AI's moves
  • Displays game status (whose turn it is, thinking state, win/tie) and a restart button

Requirements

• Python 3
• Pygame

Install Pygame with:

pip install pygame

Setup

1. Clone the repository:

   git clone https://github.com/testing-user-prog/TicTacToe.git
   cd TicTacToe

2. Make sure you have an OpenSans-Regular.ttf font file in the project directory (used for rendering text in the game window). Add it if it's missing.
3. Run the game:

   python runner.py

How to Play

1. Launch the game — you'll be prompted to choose to play as X or O.
2. Click on an empty tile to make your move.
3. The AI will respond automatically using the Minimax algorithm.
4. The game announces a winner or a tie when it ends.
5. Click "Play Again" to start a new round.

License

This project is open source and available for anyone to use or modify.