 Tic-tac-toe

A two-player game on nine positions arranged in a three-by-three grid. Players alternate marking empty positions and stop when one has a full row, column or diagonal, or when the board is full. A game search must stop at the first win. Distinct move histories can reach the same position; canonical occupancy sets or bitboards make that equality available to memoization. Quotienting by board symmetry changes the requested output unless distinct oriented positions are subsequently restored.

Tic-tac-toe is a simple, traditional two-player game played on a 3x3 grid. The objective of the game is for one player to place three of their marks (either an "X" or an "O") in a row—horizontally, vertically, or diagonally—before the other player does.