private Object minimax(GameTree <Object> node, int depth, bool maximizingPlayer, IGame game)
{
if (depth == 0 || node.IsTerminal())
{
return(node.getData());
}
if (maximizingPlayer)
{
int bestValue = -10000;
Object bestState = (Object) new Object();
foreach (GameTree <Object> item in node)
{
Object val = minimax(item, depth - 1, false, game);
//bestValue = Math.Max(bestValue, game.Evaluate(val));
int tmp = game.Evaluate(val);
if (bestValue < tmp)
{
bestValue = tmp;
bestState = item.getData();
}
}
return(bestState);
}
else
{
int bestValue = 10000;
Object bestState = (Object) new Object();
foreach (GameTree <Object> item in node)
{
Object val = minimax(item, depth - 1, true, game);
//bestValue = Math.Min(bestValue, val);
int tmp = game.Evaluate(val);
if (bestValue > tmp)
{
bestValue = tmp;
bestState = item.getData();
}
}
return(bestState);
}
}
private Object alphaBeta(GameTree <Object> node, int depth, int alpha, int beta, bool maximizingPlayer, IGame game)
{
if (depth == 0 || node.IsTerminal())
{
return(node.getData());
}
if (maximizingPlayer)
{
int v = -10000;
Object bestState = (Object) new Object();
foreach (GameTree <Object> child in node)
{
Object tmp = alphaBeta(child, depth - 1, alpha, beta, false, game);
//v = Math.Max(game.Evaluate(bestState), game.Evaluate(tmp));
int t = game.Evaluate(tmp);
if (v < t)
{
v = t;
bestState = child.getData();
}
//alpha = Math.Max(alpha, v);
if (alpha < v)
{
alpha = v;
//bestState = child.getData();
}
if (beta < alpha)
{
break;
}
}
return(bestState);
}
else
{
int v = 1000;
Object bestState = (Object) new Object();
foreach (GameTree <Object> child in node)
{
Object tmp = alphaBeta(child, depth - 1, alpha, beta, false, game);
int t = game.Evaluate(tmp);
//v = Math.Min(v, alphaBeta(child, depth - 1, alpha, beta, true, game));
if (v > t)
{
v = t;
bestState = child.getData();
}
//beta = Math.Min(beta, v);
if (beta > v)
{
beta = v;
//bestState = child.getData();
}
if (beta <= alpha)
{
break;
}
}
return(bestState);
}
}