public BFNode(BFNode parent, Action action, State state)
{
this.State = state;
this.Parent = parent;
this.Action = action;
if (this.Parent != null && this.Action != null)
this.PathCost = this.Parent.PathCost + action.Cost;
this.EstimatedTotalPathCost = this.PathCost;
}
public static int Search(List<State> states, List<Action> actions, State start, Tile target)
{
var found = 0;
PriorityQueue<BFNode> frontier = new PriorityQueue<BFNode>();
List<State> explored = new List<State>();
frontier.Add(new BFNode(start));
while (frontier.Count > 0)
{
// Chooses the lowest-cost node in the frontier
BFNode currentBFNode = frontier.Pop();
// Win condition
if (currentBFNode.State.Type.Equals(target))
found++;
explored.Add(currentBFNode.State);
// Filter actions to the ones connected to the current node
foreach (Action action in actions.Where(a => a.StateA.Equals(currentBFNode.State)))
{
// One of A or B will be the currentBFNode's action
// but it won't be added to the frontier since it
// is already in explored
var childA = new BFNode(currentBFNode, action, action.StateA);
var childB = new BFNode(currentBFNode, action, action.StateB);
if (!explored.Contains(childA.State) && !frontier.Any(n => n.State == childA.State))
frontier.Add(childA);
if (!explored.Contains(childB.State) && !frontier.Any(n => n.State == childB.State))
frontier.Add(childB);
}
}
return found;
}
public BFNode(BFNode parent, Action action)
: this(parent, action, action.StateA)
{
}