public Tuple <int, int> minimaxVal(Board b, int d, int alpha, int beta, ParallelOptions po)
{
// Base case
if (b.gameOver() || d == 0)
{
return(Tuple.Create(0, evaluate(b)));
}
// Cancel process if time is up
po.CancellationToken.ThrowIfCancellationRequested();
// Initalize variables to make minimax code shorter
bool myTurn = b.whoseMove() == position;
int bestMove = -1;
int offset = myTurn ? offsets.Item1 : offsets.Item2;
int bestVal = myTurn ? int.MinValue : int.MaxValue;
// Minimaxing
for (int move = 0 + offset; move <= 5 + offset; move++)
{
if (b.legalMove(move))
{
Board b1 = new Board(b);
b1.makeMove(move, false);
Tuple <int, int> res = minimaxVal(b1, d - 1, alpha, beta, po);
if (miniMaxCompare(res.Item2, bestVal, myTurn))
{
bestMove = move;
bestVal = res.Item2;
}
// Update alpha or beta
if (myTurn)
{
alpha = Math.Max(alpha, bestVal);
}
else
{
beta = Math.Min(beta, bestVal);
}
// Prune the tree
if (beta <= alpha)
{
break;
}
}
}
return(Tuple.Create(bestMove, bestVal));
}
public override int chooseMove(Board b)
{
if (b.whoseMove() == Position.Top)
{
for (int i = 12; i >= 7; i--) // try first go-again
{
if (b.stonesAt(i) == 13 - i)
{
return(i);
}
}
for (int i = 12; i >= 7; i--) // otherwise, first
{
if (b.stonesAt(i) > 0)
{
return(i); // available move
}
}
}
else
{
for (int i = 5; i >= 0; i--)
{
if (b.stonesAt(i) == 6 - i)
{
return(i);
}
}
for (int i = 5; i >= 0; i--)
{
if (b.stonesAt(i) > 0)
{
return(i);
}
}
}
return(-1); // an illegal move if there aren't any legal ones
} // this can't happen unless game is over
/*
* Play one Kalah game with the two given players, with firstPlayer
* starting. This function returns TOP's score.
*/
public static int playGame(Player pTop, Player pBot, Position firstPlayer)
{
b = new Board(firstPlayer);
if (firstPlayer == Position.Top)
{
Console.WriteLine("Player " + pTop.getName() + " starts.");
}
else
{
Console.WriteLine("Player " + pBot.getName() + " starts.");
}
b.display();
while (!b.gameOver())
{
Console.WriteLine();
if (b.whoseMove() == Position.Top)
{
move = pTop.chooseMove(b);
Console.WriteLine(pTop.getName() + " chooses move " + move);
}
else
{
move = pBot.chooseMove(b);
Console.WriteLine(pBot.getName() + " chooses move " + move);
}
b.makeMove(move, true); // last parameter says to be chatty
b.display();
if (b.gameOver())
{
if (b.winner() == Position.Top)
{
Console.WriteLine("Player " + pTop.getName() +
" (TOP) wins " + b.scoreTop() + " to " + b.scoreBot());
}
else if (b.winner() == Position.Bottom)
{
Console.WriteLine("Player " + pBot.getName() +
" (BOTTOM) wins " + b.scoreBot() + " to " + b.scoreTop());
}
else
{
Console.WriteLine("A tie!");
}
}
else
if (b.whoseMove() == Position.Top)
{
Console.WriteLine(pTop.getName() + " to move.");
}
else
{
Console.WriteLine(pBot.getName() + " to move.");
}
}
return(b.scoreTop());
}