/// <summary>
/// Raise the level of the edge, optionally inserting into higher level trees
/// </summary>
public void RaiseLevel()
{
// Update position in edge lists
source.RemoveEdge(this);
dest.RemoveEdge(this);
level++;
EdgeListUtility.InsertEdge(source.adjacent, this);
EdgeListUtility.InsertEdge(dest.adjacent, this);
// Update flags for s
if (source.euler.Count <= level)
{
source.euler.Add(EulerVertex <DynamicNode <T> > .Create(source));
}
var es = source.euler[level];
es.SetFlag(true);
// Update flags for t
if (dest.euler.Count <= level)
{
dest.euler.Add(EulerVertex <DynamicNode <T> > .Create(dest));
}
var et = dest.euler[level];
et.SetFlag(true);
// If the edge is already part of a spanning tree, relink them in the next level
if (euler != null)
{
euler.Add(es.Link(et, this));
}
}
/// <summary>
/// Remove edge from adjacent list
/// </summary>
public void RemoveEdge(DynamicEdge <T> edge)
{
var adj = adjacent;
int idx = EdgeListUtility.Index(adj, edge);
adj.RemoveAt(idx);
// Check if flag needs to be updated
if (!((idx < adj.Count && adj[idx].level == edge.level) ||
(idx > 0 && adj[idx - 1].level == edge.level)))
{
euler[edge.level].SetFlag(false);
}
}
public DynamicEdge <T> Link(DynamicVertex <T> other, T value)
{
var e = new DynamicEdge <T>(value, KeyCounter, this, other);
KeyCounter++;
if (!euler[0].IsConnected(other.euler[0]))
{
e.LinkSpanningForests();
}
euler[0].SetFlag(true);
other.euler[0].SetFlag(true);
EdgeListUtility.InsertEdge(adjacent, e);
EdgeListUtility.InsertEdge(other.adjacent, e);
return(e);
}
/// <summary>
/// Search over Tv for edge connecting to Tw
/// </summary>
private bool Visit(TreapNode <EulerNode <DynamicNode <T> > > node, int level)
{
if (node.flag)
{
var v = node.val.value as DynamicVertex <T>;
var adj = v.adjacent;
int ptr = EdgeListUtility.LevelIndex(adj, level);
for (; ptr < adj.Count && adj[ptr].level == level; ptr++)
{
var e = adj[ptr];
var es = e.source;
var et = e.dest;
if (es.euler[level].IsConnected(et.euler[level]))
{
// Raise edge level if dest is in current tree
e.RaiseLevel();
ptr--;
}
else
{
// Otherwise, connect trees and finish, because dest is in target tree
e.LinkSpanningForests();
return(true);
}
}
}
if (node.left != null && node.left.flagAggregate)
{
if (Visit(node.left, level))
{
return(true);
}
}
if (node.right != null && node.right.flagAggregate)
{
if (Visit(node.right, level))
{
return(true);
}
}
return(false);
}
