public void DeleteEdge(String s1, String s2)
{
VertexNode u = FindVertex(s1);
if (u == null || u.firstEdge == null)
{
Console.WriteLine("Start vertex / edge not present.");
return;
}
if (u.firstEdge.endVertex.name.Equals(s2))
{
u.firstEdge = u.firstEdge.nextEdge;
e--;
return;
}
EdgeNode q = u.firstEdge;
while (q.nextEdge != null)
{
if (q.nextEdge.endVertex.name.Equals(s2))
{
q.nextEdge = q.nextEdge.nextEdge;
e--;
return;
}
q = q.nextEdge;
}
Console.WriteLine("Edge not found.");
}
private void DeletefromEdgeLists(String s)
{
for (VertexNode p = start; p != null; p = p.nextVertex)
{
if (p.firstEdge == null)
{
continue;
}
if (p.firstEdge.endVertex.name.Equals(s))
{
p.firstEdge = p.firstEdge.nextEdge;
e--;
}
else
{
EdgeNode q = p.firstEdge;
while (q.nextEdge != null)
{
if (q.nextEdge.endVertex.name.Equals(s))
{
q.nextEdge = q.nextEdge.nextEdge;
}
}
}
}
}
public bool EdgeExists(String s1, String s2)
{
VertexNode u = FindVertex(s1);
EdgeNode curEdge = u.firstEdge;
while (curEdge != null)
{
if (curEdge.endVertex.name.Equals(s2))
{
return(true);
}
curEdge = curEdge.nextEdge;
}
return(false);
}
public int OutDegree(String s)
{
VertexNode u = FindVertex(s);
if (u == null)
{
throw new System.InvalidOperationException("Invalid vertex");
}
int outd = 0;
EdgeNode q = u.firstEdge;
while (q != null)
{
q = q.nextEdge;
outd++;
}
return(outd);
}
private void DeletefromVertexList(String s)
{
if (start == null)
{
Console.WriteLine("No vertices to be deleted.");
return;
}
if (start.name.Equals(s)) // Vertex to be deleted is first vertex of list
{
for (EdgeNode q = start.firstEdge; q != null; q = q.nextEdge)
{
e--;
}
start = start.nextVertex;
n--;
}
else
{
VertexNode p = start;
while (p.nextVertex != null)
{
if (p.nextVertex.name.Equals(s))
{
break;
}
p = p.nextVertex;
}
if (p.nextVertex == null)
{
Console.WriteLine("vertex not found.");
return;
}
else
{
for (EdgeNode q = p.nextVertex.firstEdge; q != null; q = q.nextEdge)
{
e--;
}
p.nextVertex = p.nextVertex.nextVertex;
n--;
}
}
}
public void InsertEdge(String s1, String s2)
{
if (s1.Equals(s2))
{
Console.WriteLine("Invalid edge - start and end vertices are same");
return;
}
VertexNode u = FindVertex(s1);
VertexNode v = FindVertex(s2);
if (u == null || v == null)
{
Console.WriteLine("Start or End vertex not present");
return;
}
EdgeNode temp = new EdgeNode(v);
if (u.firstEdge == null)
{
u.firstEdge = temp;
e++;
}
else
{
EdgeNode p = u.firstEdge;
while (p.nextEdge != null)
{
if (p.endVertex.name.Equals(s2))
{
Console.WriteLine("Edge present.");
return;
}
p = p.nextEdge;
}
if (p.endVertex.name.Equals(s2))
{
Console.WriteLine("edge present.");
return;
}
p.nextEdge = temp;
e++;
}
}
public int InDegree(String s)
{
VertexNode u = FindVertex(s);
if (u == null)
{
throw new System.InvalidOperationException("Invalid vertex");
}
int ind = 0;
for (VertexNode p = start; p != null; p = p.nextVertex)
{
for (EdgeNode q = p.firstEdge; q != null; q = q.nextEdge)
{
if (q.endVertex.name.Equals(s))
{
ind++;
}
}
}
return(ind);
}
