private TreeNode <T> Remove(TreeNode <T> parent, T key)
{
if (parent == null)
{
return(parent);
}
if (parent.CompareTo(key) > 0)
{
parent.Left = Remove(parent.Left, key);
}
else if (parent.CompareTo(key) < 0)
{
parent.Right = Remove(parent.Right, key);
}
else
{
if (parent.Left == null)
{
return(parent.Right);
}
else if (parent.Right == null)
{
return(parent.Left);
}
parent.Value = MinValue(parent.Right);
ElementRemoved?.Invoke(this, new TreeEventArgs <T>(key, "Element removed"));
parent.Right = Remove(parent.Right, parent.Value);
}
return(parent);
}
/// <summary>
/// Adds element to the tree according to comparer
/// </summary>
/// <param name="item">Object that should be added in tree</param>
/// <exception cref="ArgumentNullException">Thrown if parameter was null</exception>
public void Add(T item)
{
if (item is null)
{
throw new ArgumentNullException(nameof(item));
}
var newNode = new TreeNode <T>(_comparer)
{
Value = item
};
TreeNode <T> before = null;
var after = _head;
while (after != null)
{
before = after;
if (_comparer.Compare(after.Value, item) > 0)
{
after = after.Left;
}
else if (_comparer.Compare(after.Value, item) < 0)
{
after = after.Right;
}
else if (_comparer.Compare(item, after.Value) == 0)
{
while (!(after is null))
{
if (after.Right is null)
{
after.Right = newNode;
Count++;
ElementAdded?.Invoke(this, new TreeEventArgs <T>(item, "Aded"));
return;
}
after = after.Right;
}
}
}
if (_head == null)
{
_head = newNode;
}
else
{
if (before.CompareTo(item) > 0)
{
before.Left = newNode;
}
else
{
before.Right = newNode;
}
}
ElementAdded?.Invoke(this, new TreeEventArgs <T>(item, "Aded"));
Count++;
}