private void BuildTree(KnapsackNode node, KnapsackItem[] ksItems)
{
//if possible add contents of next ksitem to node
// if so recruse with remaining items
// if not determine if best and set if so
//also, recurse with unchanged node items and remaining items
if (ksItems.Length == 0) return;
var item = ksItems.First();
var newValue = node.AccumulatedValue + item.Value;
var newWeight = node.AccumulatedWeight + item.Weight;
var remainingCapacity = _capacity - newWeight;
var rest = ksItems.Skip(1).ToArray();
//if i was able to add something
if (remainingCapacity >= 0)
{
var newNode = new KnapsackNode(newValue, newWeight);
newNode.SelectedItems.AddRange(node.SelectedItems);
newNode.SelectedItems.Add(item.Id);
if (remainingCapacity > 0) BuildTree(newNode, rest);
if (newNode.AccumulatedValue > _bestNode.AccumulatedValue) _bestNode = newNode;
}
//this is to use first node but not adding current item
if (rest.Any(k => k.Weight + node.AccumulatedWeight <= _capacity) && (rest.Sum(k => k.Value) + node.AccumulatedValue) > _bestNode.AccumulatedValue)
{
BuildTree(node, rest);
}
}
