public TMetric Search(TNode node, int depth, TMetric alfa, TMetric beta, TState state, CancellationToken ct)
{
ct.ThrowIfCancellationRequested();
if (node.Children == null && depth > 0)
{
_brancher.Branch(node, state);
}
if (depth == 0 || node.Children.Length == 0)
{
var result = _evaluator.Evaluate(state);
node.Result = result;
return(result);
}
if (node.IsMaxPlayer)
{
var maxVal = _minValue;
foreach (var child in node.Children)
{
var childState = _stateTransitions.GoDown(state, child);
var result = Search(child, depth - 1, alfa, beta, childState, ct);
state = _stateTransitions.GoUp(childState, child);
if (!_comparator.IsBigger(maxVal, result))
{
maxVal = result;
node.BestChild = child;
}
if (!_comparator.IsBigger(beta, result))
{
break;
}
alfa = _comparator.IsBigger(result, alfa) ? result : alfa;
}
// todo - refactor - remove extra variables
node.Result = maxVal;
return(maxVal);
}
var minVal = _maxValue;
foreach (var child in node.Children)
{
var childState = _stateTransitions.GoDown(state, child);
var result = Search(child, depth - 1, alfa, beta, childState, ct);
state = _stateTransitions.GoUp(childState, child);
if (!_comparator.IsBigger(result, minVal))
{
minVal = result;
node.BestChild = child;
}
if (!_comparator.IsBigger(result, alfa))
{
break;
}
beta = _comparator.IsBigger(beta, result) ? result : beta;
}
// todo - refactor - remove extra variables
node.Result = minVal;
return(minVal);
}