ai-connect4

A Connect Four rules and search library built on two bitboards.

Play against it compiled to Wasm here: https://thegustafson.com/games/connect-four

Self-play

The selfplay binary runs deterministic paired-color matches. Each opening is played twice with the engines swapping Red and Yellow.

cargo run --release --bin selfplay -- \
  --a maximum --b expert --games 12 --opening-plies 4 --seed 1

The six built-in profiles are beginner, easy, medium, hard, expert, and maximum. Use --a-depth, --a-nodes, and the corresponding --b-* options to override their limits. Library users can read the same settings with search_preset or SEARCH_PRESETS.

Use it

Add the crate to your project:

[dependencies]
ai-connect4 = "0.1"

use ai_connect4::{Algorithm, Move, Position, SearchLimits, search};

let mut position = Position::default();
position
    .make_move("4".parse::<Move>().expect("valid column"))
    .expect("legal move");

let result = search(
    position,
    Algorithm::TranspositionTable,
    SearchLimits::depth(7),
);

assert!(result.best_move.is_some());

The crate includes reversible moves, perft, alpha-beta search, move ordering, and an optional transposition table.

cargo test
cargo run

Licensed under the MIT License.