Unbeatable Tic-Tac-Toe

A tic-tac-toe game in the browser where you play O against an AI that never loses. Before every move, the AI uses the Minimax algorithm to play out every possible rest of the game and picks the move with the best guaranteed result.

You vs. AI · Minimax search over the full game tree · win, loss and draw detection with the winning line highlighted · replay · vanilla JavaScript, no dependencies.

1. A.01

   Score each finished game: +10 if the AI (X) wins, −10 if you (O) win, 0 for a draw.

2. A.02

   Try every free square, then every possible reply, recursively until each game ends.

3. A.03

   Back up the scores: on its turn the AI takes the highest (MAX); on yours it assumes you take the lowest (MIN).

4. A.04

   Play the move with the best backed-up score. The 9-square board is small enough to search the whole tree, with no depth limit.

Unbeatable Tic-Tac-Toe: Minimax on a real position: X wins at once (+10) instead of blocking (0) or losing (−10)

Unbeatable Tic-Tac-Toe: One slip and the AI completes the line

Unbeatable Tic-Tac-Toe: New game: you play O and move first

Unbeatable Tic-Tac-Toe: Best play on both sides ends in a draw

› swipe for all 4 screens

Game engine

✓Minimax · full game tree

Front end

✓Vanilla JS · HTML · CSS

Platform

✓Vercel