// Find, with path halving: avoids recursion
public Eqclass <T> Find()
{
if (link == null)
{
return(this);
}
else if (link.link == null)
{
return(link);
}
else
{
// Grandparent, parent, and link
Eqclass <T> pp = this, p = link, plink = p.link;
while (plink != null)
{
// Invariant: pp -> p -> plink
pp.link = plink;
pp = p;
p = plink;
plink = p.link;
}
return(p);
}
}
public static Eqclass <T> Make(T item)
{
Eqclass <T> result;
if (!dict.Find(item, out result))
{
dict[item] = result = new Eqclass <T>(item);
}
return(result);
}
public static void Main(String[] args)
{
Eqclass <int> x = Eqclass <int> .Make(3),
y = Eqclass <int> .Make(4),
z = Eqclass <int> .Make(5);
x.Union(y);
y.Union(z);
Console.WriteLine(x.Find().Item);
Console.WriteLine(y.Find().Item);
Console.WriteLine(z.Find().Item);
}
public void Union(Eqclass <T> that)
{
Eqclass <T> thatRep = that.Find(), thisRep = this.Find();
if (thatRep != thisRep)
{
if (thatRep.rank == thisRep.rank)
{
thisRep.link = thatRep;
thatRep.rank++;
}
else if (thatRep.rank > thisRep.rank)
{
thisRep.link = thatRep;
}
else
{
thatRep.link = thisRep;
}
}
}
