public void Add(T item)
{
int lvl = coinflip.Next(height);
SkipNode <T> add = new SkipNode <T>(lvl + 1, item);
SkipNode <T> iter = head;
for (int i = height - 1; i >= 0; i--)
{
while (iter.Next[i] != null)
{
int diff = item.CompareTo(iter.Next[i].Item);
if (diff == 0)
{
iter.Next[i] = iter.Next[i].Next[i];
continue;
}
if (diff < 0)
{
break;
}
iter = iter.Next[i];
}
if (i <= lvl)
{
add.Next[i] = iter.Next[i];
iter.Next[i] = add;
}
}
}
public SkipList(int height = 32)
{
this.height = height;
this.head = new SkipNode <T>(height);
Clear();
}
public bool Remove(T item)
{
SkipNode <T> iter = head;
bool found = false;
for (int i = height - 1; i >= 0; i--)
{
while (iter.Next[i] != null)
{
int diff = item.CompareTo(iter.Next[i].Item);
if (diff == 0)
{
found = true;
iter.Next[i] = iter.Next[i].Next[i];
continue;
}
if (diff < 0)
{
break;
}
iter = iter.Next[i];
}
}
return(found);
}
public IEnumerator <T> GetEnumerator()
{
SkipNode <T> iter = head;
while (iter.Next[0] != null)
{
yield return(iter.Next[0].Item);
iter = iter.Next[0];
}
}
public bool Contains(T item)
{
SkipNode <T> iter = head;
for (int i = height - 1; i >= 0; i--)
{
while (iter.Next[i] != null)
{
int diff = item.CompareTo(iter.Next[i].Item);
if (diff == 0)
{
return(true);
}
if (diff < 0)
{
break;
}
iter = iter.Next[i];
}
}
return(false);
}