public int alpha_beta(State aState, ref int alpha, ref int beta, int depth, int passed)
{
int alpha_img=alpha;
int beta_img=beta;
int best_value1 = -50000;
int best_value2 = 50000;
if (depth == 0)
{
aState.EstValue = (int)evaluation(aState);
return aState.EstValue;
}
for (int i = 1; i < aState.AvailablePosition[0].Count + 1; i++)
{
aState.GenerateSingle(i);//if this child has been generated, the function won't generate it more
int value = alpha_beta(aState.Child[i], ref alpha_img, ref beta_img, depth - 1, 0);
if (aState.NextPlayer != Enemy)//get min
{
if (value < best_value2)//update best_value2
{
best_value2 = value;
}
if (best_value2 < beta )//pruning
{
aState.EstValue = best_value2;
return best_value2;
}
}
else//get max
{
if (value > best_value1)
{
best_value1 = value;
}
if (best_value1 > beta)//pruning
{
aState.EstValue = best_value1;
return best_value1;
}
}
}
if (aState.AvailablePosition[0].Count == 0)//No step to move next;
{
aState.GenerateSingle(0);
int value = alpha_beta(aState.Child[0], ref beta_img, ref alpha_img, depth - 1, 0);
if (aState.NextPlayer != Enemy)
{
best_value2 = value;
aState.EstValue = best_value2;
}
else
{
best_value1 = value;
aState.EstValue=best_value1;
}
}
//Not pruning, change alpha and beta;
if (aState.NextPlayer != Enemy)//get min
{
beta = best_value2;
aState.EstValue = beta;
return beta;
}
else
{
beta = best_value1;
aState.EstValue = beta;
return beta;
}
}
public int alpha_beta(State aState, ref int alpha, ref int beta, int depth, int passed)
{
int alpha_img = alpha;
int beta_img = beta;
int best_value1 = -50000;
int best_value2 = 50000;
if (depth == 0)
{
aState.EstValue = (int)evaluation(aState);
return(aState.EstValue);
}
for (int i = 1; i < aState.AvailablePosition[0].Count + 1; i++)
{
aState.GenerateSingle(i);//if this child has been generated, the function won't generate it more
int value = alpha_beta(aState.Child[i], ref alpha_img, ref beta_img, depth - 1, 0);
if (aState.NextPlayer != Enemy) //get min
{
if (value < best_value2) //update best_value2
{
best_value2 = value;
}
if (best_value2 < beta) //pruning
{
aState.EstValue = best_value2;
return(best_value2);
}
}
else//get max
{
if (value > best_value1)
{
best_value1 = value;
}
if (best_value1 > beta)//pruning
{
aState.EstValue = best_value1;
return(best_value1);
}
}
}
if (aState.AvailablePosition[0].Count == 0)//No step to move next;
{
aState.GenerateSingle(0);
int value = alpha_beta(aState.Child[0], ref beta_img, ref alpha_img, depth - 1, 0);
if (aState.NextPlayer != Enemy)
{
best_value2 = value;
aState.EstValue = best_value2;
}
else
{
best_value1 = value;
aState.EstValue = best_value1;
}
}
//Not pruning, change alpha and beta;
if (aState.NextPlayer != Enemy)//get min
{
beta = best_value2;
aState.EstValue = beta;
return(beta);
}
else
{
beta = best_value1;
aState.EstValue = beta;
return(beta);
}
}
