public int CountConnectedComponents()
{
int componentCount = 0;
int componentNumber = 1;
Dictionary <T, int> components = new Dictionary <T, int>();
HashSet <UnorderedPair <int> > merged = new HashSet <UnorderedPair <int> >();
foreach (UnorderedPair <T> edge in _edges)
{
bool containsFirst = components.ContainsKey(edge.First);
bool containsSecond = components.ContainsKey(edge.Second);
if (!containsFirst && !containsSecond)
{
// New edge; create a new component.
components.Add(edge.First, componentNumber);
components.Add(edge.Second, componentNumber);
componentNumber++;
componentCount++;
}
else if (containsFirst && containsSecond)
{
if (components[edge.First] != components[edge.Second])
{
UnorderedPair <int> record = new UnorderedPair <int>(components[edge.First], components[edge.Second]);
// Merge two components.
if (!merged.Contains(record))
{
merged.Add(record);
componentCount--;
}
}
}
else if (containsFirst)
{
if (components.ContainsKey(edge.Second))
{
components[edge.Second] = components[edge.First];
}
else
{
components.Add(edge.Second, components[edge.First]);
}
}
else if (containsSecond)
{
if (components.ContainsKey(edge.First))
{
components[edge.First] = components[edge.Second];
}
else
{
components.Add(edge.First, components[edge.Second]);
}
}
}
return(componentCount + (_vertices.Count - components.Count));
}
public bool DeleteEdge(UnorderedPair <T> edge)
{
return(_edges.Remove(edge));
}
public bool AddEdge(UnorderedPair <T> edge)
{
return(_edges.Add(edge));
}
public bool Equals(UnorderedPair <T> pair)
{
return(_first.Equals(pair._first) && _second.Equals(pair._second));
}
