internal TreapNode ChangeKth(uint k, T value)
{
uint pos = left != null ? left.size : 0;
int b = k.CompareTo(pos);
if (b == 0)
{
TreapNode tmp = new TreapNode(this);
tmp.value = value;
return(tmp);
}
else if (b < 0)
{
return(new TreapNode(this, left.ChangeKth(k, value), right));
}
else
{
return(new TreapNode(this, left, right.ChangeKth(k - pos - 1, value)));
}
}
public PersistentMap <K, T> ChangeKth(uint pos, T value)
{
return(new PersistentTreapMap <K, T>(root.ChangeKth(pos, value)));
}
