public void CreateEmptyDirectedGraphAndAddVertices()
{
var graph = new DirectedGraph();
Assert.AreEqual(0, graph.Vertices());
Assert.AreEqual(0, graph.Edges());
int vertex1id = graph.AddVertex();
int vertex2id = graph.AddVertex();
Assert.AreEqual(0, vertex1id);
Assert.AreEqual(1, vertex2id);
graph.AddEdge(0, 1);
Assert.AreEqual(2, graph.Vertices());
Assert.AreEqual(1, graph.Edges());
Assert.IsTrue(graph.AdjacentVertices(0).Contains(1));
Assert.IsFalse(graph.AdjacentVertices(1).Contains(0));
// add the same edge again
graph.AddEdge(1, 0);
Assert.AreEqual(2, graph.Vertices());
Assert.AreEqual(2, graph.Edges());
Assert.IsTrue(graph.AdjacentVertices(0).Contains(1));
Assert.IsTrue(graph.AdjacentVertices(1).Contains(0));
}
public void CreateDirectedGraphWithSelfLoops()
{
var graph = new DirectedGraph(1);
Assert.AreEqual(1, graph.Vertices());
Assert.AreEqual(0, graph.Edges());
graph.AddEdge(0, 0);
Assert.AreEqual(1, graph.Edges());
Assert.IsTrue(graph.AdjacentVertices(0).Contains(0));
}
public void CreateDirectedGraph()
{
// a cube
var graph = new DirectedGraph(4);
graph.AddEdge(0, 1);
graph.AddEdge(1, 2);
graph.AddEdge(2, 3);
graph.AddEdge(3, 0);
Assert.AreEqual(4, graph.Vertices());
Assert.AreEqual(4, graph.Edges());
Assert.IsTrue(graph.AdjacentVertices(0).Contains(1));
Assert.IsTrue(graph.AdjacentVertices(1).Contains(2));
Assert.IsTrue(graph.AdjacentVertices(2).Contains(3));
Assert.IsTrue(graph.AdjacentVertices(3).Contains(0));
// no linkback
Assert.IsFalse(graph.AdjacentVertices(0).Contains(3));
}
public List <List <int> > GetPossiblePaths <T, K>(DirectedGraph <T, K> graph)
{
var edges = graph.GetEdgeSet().ToList();
var start = edges[0].GetFirst();
var visited = new HashSet <T>();
var stack = new Stack <T>();
stack.Push(start);
var previousVertexModulo = graph.GetVertexModulo(start);
var allPathsAsVertexKeys = new List <List <int> >();
var allPathsAsVertexValues = new List <List <int> >();
var newPathToAdd = new List <T>();
while (stack.Count > 0)
{
var vertex = stack.Pop();
if (visited.Contains(vertex))
{
continue;
}
visited.Add(vertex);
var adjacentVertices = graph.AdjacentVertices(vertex).ToList();
previousVertexModulo = graph.GetVertexModulo(vertex);
var deadEndCounter = 0;
foreach (var neighbor in adjacentVertices)
{
var neighborVertex = graph.GetVertexPair(neighbor);
var currentLevel = graph.GetWeight(vertex, neighborVertex.Key).GetHashCode();
if (newPathToAdd.Count > currentLevel)
{
for (var i = newPathToAdd.Count + 1 - currentLevel; i > 0; i--)
{
newPathToAdd.RemoveAt(newPathToAdd.Count - i);
}
}
var neighborModulo = graph.GetVertexModulo(neighbor);
if (!visited.Contains(neighbor) && previousVertexModulo != neighborModulo)
{
stack.Push(neighbor);
if (!newPathToAdd.Contains(vertex))
{
newPathToAdd.Add(vertex);
}
}
else
{
deadEndCounter++;
}
if (deadEndCounter == 2)
{
visited.Remove(vertex);
}
}
if (adjacentVertices.Count != 0)
{
continue;
}
if (allPathsAsVertexKeys.Count != 0 && newPathToAdd.Count == allPathsAsVertexKeys[0].Count)
{
newPathToAdd.RemoveAt(newPathToAdd.Count - 1);
}
newPathToAdd.Add(vertex);
allPathsAsVertexKeys.Add(newPathToAdd.ConvertAll(x => x.GetHashCode()).ToList());
var newList = new List <int>();
newPathToAdd.ForEach(x => newList.Add(graph.GetVertexPair(x).Value.GetHashCode()));
allPathsAsVertexValues.Add(newList);
}
return(allPathsAsVertexValues);
}
