public bool CanFind(int startingVertex, int goalVertex)
{
if (startingVertex > GraphToSearch.NumberOfVertices || goalVertex > GraphToSearch.NumberOfVertices)
{
throw new InvalidOperationException();
}
StartingVertex = startingVertex;
Goal = goalVertex;
//ideally this should be a priority queue
var priorityQueue = new List <Tuple <int, int> >();
//list of visited
var dictionaryOfVisited = new Dictionary <int, int>();
var cummulativeDistance = 0;
//Initially start with 0 weight - sorted dictionary sorts the values based on keys
priorityQueue.Add(new Tuple <int, int>(startingVertex, cummulativeDistance));
while (priorityQueue.Count != 0)
{
var node = priorityQueue.OrderBy(n => n.Item2).First();
priorityQueue.Remove(node);
if (node.Item1 == goalVertex)
{
return(true);
}
//Have we seen this node before, if so unwind the stack as we do not want to explore this node again
if (dictionaryOfVisited.ContainsKey(node.Item1))
{
continue;
}
//Otherwise update distance and add to visited
cummulativeDistance = cummulativeDistance + node.Item2;
dictionaryOfVisited.Add(node.Item1, node.Item1);
//search for neighbours
var listOfNeighbours = GraphToSearch.GetNeighbours(node.Item1);
foreach (var neighbour in listOfNeighbours.Where(n => !dictionaryOfVisited.ContainsKey(n)))
{
priorityQueue.Add(new Tuple <int, int>(neighbour, GraphToSearch.GetEdgeWeight(node.Item1, neighbour) + cummulativeDistance));
ParentMap.AddOrUpdate(neighbour, node.Item1);
}
}
return(false);
}
public bool CanFind(int startingVertex, int goalVertex)
{
if (startingVertex > GraphToSearch.NumberOfVertices || goalVertex > GraphToSearch.NumberOfVertices)
{
throw new InvalidOperationException();
}
StartingVertex = startingVertex;
Goal = goalVertex;
//stack of vertex to search next
var queue = new Queue <int>();
//list of visited
var dictionaryOfVisited = new Dictionary <int, int>();
queue.Enqueue(startingVertex);
while (queue.Count > 0)
{
var currentVertex = queue.Dequeue();
//Have we reached the goal
if (currentVertex == goalVertex)
{
return(true);
}
//Have we seen this node before, if so unwind the stack as we do not want to explore this node again
if (dictionaryOfVisited.ContainsKey(currentVertex))
{
continue;
}
//Otherwise add to visited
dictionaryOfVisited.Add(currentVertex, currentVertex);
//search for neighbours
var listOfNeighbours = GraphToSearch.GetNeighbours(currentVertex);
foreach (var neighbour in listOfNeighbours.Where(n => !dictionaryOfVisited.ContainsKey(n)))
{
queue.Enqueue(neighbour);
ParentMap.AddOrUpdate(neighbour, currentVertex);
if (neighbour == goalVertex)
{
return(true);
}
}
}
return(false);
}
