public Node <E, A, C> Search()
{
HashSet <E> explored = new HashSet <E>();
//! first node in the frontier is the InitialState
Node <E, A, C> node = new Node <E, A, C>(problem.InitialState);
Console.Write("Initial node: ");
Console.WriteLine(node.state.ToString());
//! if it happens to be the goal state, return it, we're done
if (problem.GoalTest(node.state))
{
return(node);
}
//C heur = heurfun(node);
frontier.Append(/*heur,*/ node);
while (frontier.Count() > 0 /*&& frontier.Count() < 100*/)
{
node = frontier.Pop();
if (node == null)
{
NPuzzleUtils.NullSearchNodeException ex = new NPuzzleUtils.NullSearchNodeException("Node popper off frontier is null");
throw ex;
}
int[] s = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
if (problem.GoalTest(node.state))
{
return(node);
}
explored.Add(node.state);
//Console.WriteLine("Popped from frontier: {0}", node.state.ToString());
node.Expand(problem).ForEach(
delegate(Node <E, A, C> n)
{
// heur = heurfun(n);
bool inPriorityQueue = frontier.InPriorityQueue(n);
if (!explored.Contains(n.state) && !inPriorityQueue)
{
//Console.WriteLine("Appending to frontier: {0}", n.state.ToString());
frontier.Append(/*heur,*/ n);
}
else if (inPriorityQueue)
{
Node <E, A, C> incumbent = frontier.GetIncumbent(n);
if (frontier.Heurfun(n).CompareTo(frontier.Heurfun(incumbent)) == 1)
{
// remove incumbent
frontier.RemoveIncumbent(incumbent);
// add n
frontier.Append(n);
}
// Console.WriteLine("It's in the frontier");
}
}
);
}
return(default(Node <E, A, C>));
}
