private static ArrayList<T3Board> directlyReachableStates(T3Board board) {
ArrayList<T3Board> drs = new ArrayList<T3Board>();
// look for reachable states
for (int row = 1; row <= 3; row++) {
for (int col = 1; col <= 3; col++) {
T3Board next = new T3Board(board);
// if space is available, mark it
if (next.markSpace(row, col, T3Board.X)) {
// switch X and O in next stage, so the agent is always X
next.switchSeats();
// add it to the list
drs.add(next);
}
}
}
return drs;
}
