/// <summary>
/// Removes the specified key from the current instance of the scapegoat tree. Rebuilds tree if it's unbalanced.
/// </summary>
/// <param name="key">Key value.</param>
/// <returns>True - if key was successfully removed, false - if the key wasn't found in the tree.</returns>
public bool Delete(TKey key)
{
if (Root == null)
{
return(false);
}
if (Remove(Root, Root, key))
{
Size--;
if (Root != null && Size < Alpha * MaxSize)
{
TreeIsUnbalanced?.Invoke(this, EventArgs.Empty);
var list = new List <Node <TKey> >();
Extensions.FlattenTree(Root, list);
Root = Extensions.RebuildFromList(list, 0, list.Count - 1);
MaxSize = Size;
}
return(true);
}
return(false);
}
/// <summary>
/// Inserts a new key into current instance of the scapegoat tree. Rebuilds tree if it's unbalanced.
/// </summary>
/// <param name="key">Key value.</param>
/// <returns>True - if insertion is successful, false - if the key is already present in the tree.</returns>
public bool Insert(TKey key)
{
var node = new Node <TKey>(key);
if (Root == null)
{
Root = node;
UpdateSizes();
return(true);
}
var path = new Stack <Node <TKey> >();
var current = Root;
var found = false;
while (!found)
{
path.Push(current);
var result = current.Key.CompareTo(node.Key);
switch (result)
{
case < 0 when current.Right != null:
current = current.Right;
continue;
case < 0:
current.Right = node;
found = true;
break;
case > 0 when current.Left != null:
current = current.Left;
continue;
case > 0:
current.Left = node;
found = true;
break;
default:
return(false);
}
}
UpdateSizes();
if (path.Count > Root.GetAlphaHeight(Alpha))
{
TreeIsUnbalanced?.Invoke(this, EventArgs.Empty);
BalanceFromPath(path);
MaxSize = Math.Max(MaxSize, Size);
}
return(true);
}
