///////    TicStrategy.java    ///////

public class TicStrategy
{
// move generate a move for self against opponent
// given the game moves already made (self and opponent)

// strategy used here:
//    Find a wining move. If no such move
//    take any wining move away from opponent.
//    If neither, make any valid move

    public int move(int self, int opponent)
    { int amove = TicGame.NOMOVE;
      if ( (self|opponent) == 0 )
         return openMove();
      for (int i = 0 ; i < 9 ; i++)
      {  int m = moves[i], mv = (1 << m);
         if ( ((self|opponent) & mv) == 0)               // open square
         {  if (TicGame.isWin(self | mv)) return m;      // self wins
            if (TicGame.isWin(opponent | mv)) amove = m; // block opponent win
            else if (amove == TicGame.NOMOVE) amove = m;
         }
      }
      return amove;  // move found
    }

    protected int openMove()
    {  return (int)(9*Math.random());
    }

    protected int[] moves = {4, 0, 2, 6, 8, 1, 3, 5, 7};
}