public override ImmutableCollection <T> AddBack(T value)
{
if (m_right.IsFull)
{
return(new NormalCollection(
m_left,
m_middle.AddBack(m_right.RemoveBack()),
new Two(m_right.Back, value)));
}
else
{
return(new NormalCollection(m_left, m_middle, m_right.AddBack(value)));
}
}
public override ImmutableCollection <T> RemoveBack()
{
if (m_right.Size > 1)
{
return(new NormalCollection(m_left, m_middle, m_right.RemoveBack()));
}
else if (!m_middle.IsEmpty)
{
return(new NormalCollection(m_left, m_middle.RemoveBack(), m_middle.Back));
}
else if (m_left.Size > 1)
{
return(new NormalCollection(m_left.RemoveBack(), ImmutableCollection <MiniCollection> .Empty, new One(m_left.Back)));
}
else
{
return(new SingleCollection(m_left.Back));
}
}