/// <summary>
/// Swap two values in an ArrayList<T> collection given their indexes.
/// </summary>
public static void Swap <T>(this ArrayListGeneric <T> list, int firstIndex, int secondIndex)
{
if (list.Count < 2 || firstIndex == secondIndex) //This check is not required but Partition function may make many calls so its for perf reason
{
return;
}
var temp = list[firstIndex];
list[firstIndex] = list[secondIndex];
list[secondIndex] = temp;
}
/// <summary>
/// A breadth first search traversal of the graph, starting from a specified vertex.
/// Returns the visited vertices of the graph.
/// </summary>
public virtual IEnumerable <T> BreadthFirstWalk(T source)
{
// Check for existence of source
if (VerticesCount == 0)
{
return(new ArrayListGeneric <T>(0));
}
else if (!HasVertex(source))
{
throw new KeyNotFoundException("The source vertex doesn't exist.");
}
var visited = new HashSet <T>();
var queue = new QueueGeneric <T>();
var listOfNodes = new ArrayListGeneric <T>(VerticesCount);
listOfNodes.Add(source);
visited.Add(source);
queue.Enqueue(source);
while (!queue.IsEmpty)
{
var current = queue.Dequeue();
var neighbors = Neighbours(current);
foreach (var adjacent in neighbors)
{
if (!visited.Contains(adjacent))
{
listOfNodes.Add(adjacent);
visited.Add(adjacent);
queue.Enqueue(adjacent);
}
}
}
return(listOfNodes);
}
/// <summary>
/// A depth first search traversal of the graph, starting from a specified vertex.
/// Returns the visited vertices of the graph.
/// </summary>
public virtual IEnumerable <T> DepthFirstWalk(T source)
{
// Check for existence of source
if (VerticesCount == 0)
{
return(new ArrayListGeneric <T>(0));
}
else if (!HasVertex(source))
{
throw new KeyNotFoundException("The source vertex doesn't exist.");
}
var visited = new HashSet <T>();
var stack = new StackGeneric <T>();
var listOfNodes = new ArrayListGeneric <T>(VerticesCount);
stack.Push(source);
while (!stack.IsEmpty)
{
var current = stack.Pop();
if (!visited.Contains(current))
{
listOfNodes.Add(current);
visited.Add(current);
foreach (var adjacent in Neighbours(current))
{
if (!visited.Contains(adjacent))
{
stack.Push(adjacent);
}
}
}
}
return(listOfNodes);
}
