/*for unconnected graph, we should iterate through all
* nodes and start DFT on each node to make sure that all nodes have been visited
* for(int 1=0; i<n;i++)
* {
* DepthFirstTraversal(graph, vistedList, adjacent);
* }
*/
public virtual void DepthFirstTraversal(GraphDS graph, int[] vistedList, int currentVertex)
{
if (vistedList[currentVertex] == 1)
{
return;
}
vistedList[currentVertex] = 1;
var adjacentList = graph.GetAdjacentVertices(currentVertex);
foreach (var adjacent in adjacentList)
{
DepthFirstTraversal(graph, vistedList, adjacent);
}
Console.WriteLine(currentVertex);
}
public List <int> TopologicalSort(GraphDS graph)
{
Queue <int> queue = new Queue <int>();
Dictionary <int, int> indegreeMap = new Dictionary <int, int>();
List <int> sortedList = new List <int>();
for (int i = 0; i < graph.Numvertices; i++)
{
var indegreeNum = graph.GetIndegree(i);
indegreeMap.Add(i, indegreeNum);
if (indegreeNum == 0)
{
queue.Enqueue(i);
}
}
while (queue.Count > 0)
{
var currentVertex = queue.Dequeue();
sortedList.Add(currentVertex);
var adjacentList = graph.GetAdjacentVertices(currentVertex);
for (int i = 0; i < adjacentList.Count; i++)
{
var updatedIndegree = graph.GetIndegree(i) - 1;
indegreeMap[i] = updatedIndegree;
if (updatedIndegree == 0)
{
queue.Enqueue(i);
}
}
}
if (sortedList.Count != graph.Numvertices)
{
throw new Exception("The graph had a cycle");
}
return(sortedList);
}
/*for unconnected graph, we should iterate through all
* nodes and start DFT on each node to make sure that all nodes have been visited
* for(int 1=0; i<n;i++)
* {
* BreadthFirstTraversal(graph, vistedList, adjacent);
* }
*/
public virtual void BreadthFirstTraversal(GraphDS graph, int[] vistedList, int currentVertex)
{
Queue <int> queue = new Queue <int>();
queue.Enqueue(currentVertex);
while (queue.Count > 0)
{
var vertex = queue.Dequeue();
if (vistedList[vertex] == 1)
{
continue;
}
Console.WriteLine(vertex);
vistedList[vertex] = 1;
var adjacentList = graph.GetAdjacentVertices(vertex);
foreach (var adjacent in adjacentList)
{
if (vistedList[vertex] != 1)
{
queue.Enqueue(adjacent);
}
}
}
}