private static IEnumerable <State> FindPath(Node[,] nodes, X_Y emptyNodePos)
{
var targetNodePos = new X_Y {
X = nodes.GetLength(0) - 1, Y = 0
};
var maxAvail = nodes[emptyNodePos.X, emptyNodePos.Y].Available;
var initState = new GraphNode
{
TargetNodePos = targetNodePos,
EmptyNodePos = emptyNodePos,
H = 0,
F = 0,
};
var endTargetNodePos = new X_Y {
X = 0, Y = 0
};
var open = new HashSetOrderedBy <GraphNode, int>((state) => state.G);
var close = new HashSet <GraphNode>();
open.Add(initState);
var count = 0;
GraphNode path = null;
while (open.Any() && path == null)
{
count++;
var currentNode = open.ValueWithMinSelector();
var children = GenerateChildren(currentNode, nodes, maxAvail, endTargetNodePos);
foreach (var child in children)
{
if (open.TryGetValue(child, out GraphNode existingNode) || close.TryGetValue(child, out existingNode))
{
if (existingNode.H <= child.H)
{
continue;
}
open.Remove(existingNode);
}
open.Add(child);
if (child.TargetNodePos.Equals(endTargetNodePos))
{
path = child;
break;
}
}
open.Remove(currentNode);
close.Add(currentNode);
yield return(new State
{
Closed = close,
Open = open,
LastClosed = currentNode,
Path = path,
});
}
}
private GraphNode SolveTSP(Dictionary <char, Dictionary <char, GraphNode> > graph, Dictionary <char, X_Y> locations, char zeroPoint, Func <GraphNode, GraphNode, bool> targetCondition)
{
GraphNode path = null;
var locationsToVisit = new string(locations.Keys.OrderBy(c => c).ToArray());
locationsToVisit = this.VisitLocation(locationsToVisit, zeroPoint);
var initState = new GraphNode
{
CurrentPos = locations[zeroPoint],
LocationsToVisit = locationsToVisit,
LastLocation = '0',
H = 0,
F = 0,
};
var returnState = new GraphNode
{
CurrentPos = locations[zeroPoint],
LocationsToVisit = string.Empty,
};
var open = new HashSetOrderedBy <GraphNode, int>((state) => state.G);
var close = new HashSet <GraphNode>();
open.Add(initState);
var count = 0;
while (open.Any())
{
count++;
var currentNode = open.ValueWithMinSelector();
var lastOpen = new LinkedList <GraphNode>();
var children = this.GenerateChildrenTSP(currentNode, graph, locations, path);
foreach (var child in children)
{
if (open.TryGetValue(child, out GraphNode existingNode) || close.TryGetValue(child, out existingNode))
{
if (existingNode.H <= child.H)
{
continue;
}
open.Remove(existingNode);
}
lastOpen.AddLast(child);
open.Add(child);
if (targetCondition(child, returnState) && (path == null || path.H > child.H))
{
path = child;
var nodesToDelete = open.Where(n => n.H >= path.H).ToList();
foreach (var nd in nodesToDelete)
{
open.Remove(nd);
}
}
}
open.Remove(currentNode);
close.Add(currentNode);
}
return(path);
}
private IEnumerable <GraphNode> SolveGraph(Dictionary <string, Dictionary <string, int> > graph)
{
GraphNode path = null;
var open = new HashSetOrderedBy <GraphNode, int>((state) => state.Cost);
var close = new HashSet <GraphNode>();
var keyToHash = new Dictionary <string, int>();
var hash = 1;
foreach (var key in graph.Keys)
{
keyToHash.Add(key, hash);
hash <<= 1;
}
var locationsToVisit = hash - 1;
foreach (var location in graph.Keys)
{
var initState = new GraphNode
{
CurrentPos = location,
LocationsToVisit = locationsToVisit - keyToHash[location],
Cost = 0,
};
open.Add(initState);
}
while (open.Any())
{
var currentNode = open.ValueWithMinSelector();
var children = this.GenerateChildren(currentNode, graph, path, keyToHash);
foreach (var child in children)
{
if (open.TryGetValue(child, out GraphNode existingNode) || close.TryGetValue(child, out existingNode))
{
if (existingNode.Cost <= child.Cost)
{
continue;
}
open.Remove(existingNode);
}
open.Add(child);
if (child.LocationsToVisit == 0)
{
path = child;
var nodesToDelete = open.Where(n => n.Cost >= path.Cost).ToList();
foreach (var nd in nodesToDelete)
{
open.Remove(nd);
}
}
}
open.Remove(currentNode);
close.Add(currentNode);
yield return(currentNode);
}
yield return(path);
}