private void Traverse(List <T> list, LinkedAvlTreeNode <T> node)
{
if (node == null)
{
return;
}
Traverse(list, node.Left);
list.Add(node.Data);
Traverse(list, node.Right);
}
private void RotateRight(out LinkedAvlTreeNode <T> node)
{
//System.Diagnostics.Trace.WriteLine("RotateRight");
LinkedAvlTreeNode <T> tmp = _right;
_right = tmp.Left;
tmp.Left = this;
node = tmp;
System.Diagnostics.Debug.Assert(node != null);
}
private void printNode(int depth, LinkedAvlTreeNode <T> node)
{
if (node == null)
{
Console.WriteLine("null");
return;
}
PrintIdent(depth); Console.WriteLine(string.Format("d: {0}", node.Data));
PrintIdent(depth); Console.Write("l:"); printNode(depth + 1, node.Left);
PrintIdent(depth); Console.Write("r:"); printNode(depth + 1, node.Right);
}
private void DoubleRotateLeft(out LinkedAvlTreeNode <T> node)
{
//System.Diagnostics.Trace.WriteLine("DoubleRotateLeft");
LinkedAvlTreeNode <T> tmp = Left.Right;
Left.Right = tmp.Left;
tmp.Left = Left;
Left = tmp.Right;
tmp.Right = this;
node = tmp;
System.Diagnostics.Debug.Assert(node != null);
}
private void UnlinkThis()
{
if (this._previous != null)
{
System.Diagnostics.Debug.Assert(Previous.Next == this);
this._previous._next = this._next;
}
if (this._next != null)
{
System.Diagnostics.Debug.Assert(Next.Previous == this);
this._next._previous = this._previous;
}
this._next = null;
this._previous = null;
}
public LinkedAvlTreeNode <T> Find(T data)
{
LinkedAvlTreeNode <T> parent;
int comparison = -1;
LinkedAvlTreeNode <T> result = null;
if (_root != null)
{
result = _root.Find(data, out parent, out comparison);
}
if (comparison != 0)
{
throw new KeyNotFoundException();
}
return(result);
}
private void SwapDataWithNextSmaller(LinkedAvlTreeNode <T> parent, LinkedAvlTreeNode <T> node)
{
LinkedAvlTreeNode <T> bigger = node._right;
while (bigger != null)
{
node = bigger;
bigger = node._right;
}
T tmp = node._data;
node._data = parent._data;
parent._data = tmp;
node.UnlinkThis();
}
internal LinkedAvlTreeNode <T> Find(T data, out LinkedAvlTreeNode <T> parent, out int comparison)
{
comparison = this.Data.CompareTo(data);
parent = this;
if (comparison < 0 && _right != null)
{
return(_right.Find(data, out parent, out comparison));
}
if (comparison > 0 && _left != null)
{
return(_left.Find(data, out parent, out comparison));
}
if (comparison == 0)
{
return(this);
}
return(null);
}
public void Add(T data)
{
lock (_synchRoot)
{
bool dataAdded = true;
if (_count == 0)
{
_root = new LinkedAvlTreeNode <T>(data);
}
else
{
_root.AddData(data, out _root, out dataAdded);
}
if (dataAdded)
{
_count++;
}
}
}
internal bool AddData(T data, out LinkedAvlTreeNode <T> node, out bool added)
{
int comparison = this.Data.CompareTo(data);
if (comparison < 0)
{
return(AddChildRight(data, out node, out added));
}
else if (comparison > 0)
{
return(AddChildLeft(data, out node, out added));
}
else // same
{
node = this;
added = false;
return(false);
}
}
private void AdjustBalance(LinkedAvlTreeNode <T> node)
{
int oldBalance = node._balance;
node._balance = 0;
if (oldBalance == 0)
{
node.Left._balance = 0;
node.Right._balance = 0;
}
else if (oldBalance == 1)
{
node.Right._balance = 0;
node.Left._balance = -1;
}
else
{
node.Right._balance = 1;
node.Left._balance = 0;
}
}
public LinkedAvlTreeNode <T> UpperBound(T data)
{
if (_root == null)
{
return(null);
}
LinkedAvlTreeNode <T> parent;
int comparison;
LinkedAvlTreeNode <T> result = _root.Find(data, out parent, out comparison);
if (comparison == 0)
{
return(result);
}
else if (comparison < 0 && parent.Next != null)
{
return(parent.Next);
}
else
{
return(parent);
}
}
internal bool DeleteElement(T data, out LinkedAvlTreeNode <T> node, out bool heightDecreased)
{
bool deletedLeft = true;
bool elementDeleted = false;
node = this;
int comparison = this.Data.CompareTo(data);
if (comparison > 0 && _left != null)
{
elementDeleted = _left.DeleteElement(data, out _left, out heightDecreased);
}
else if (comparison < 0 && _right != null)
{
elementDeleted = _right.DeleteElement(data, out _right, out heightDecreased);
deletedLeft = false;
}
else if (comparison == 0)
{
if (_left == null)
{
UnlinkThis();
node = _right; heightDecreased = true;
return(true);
}
else if (_right == null)
{
UnlinkThis();
node = _left; heightDecreased = true;
return(true);
}
else
{
SwapDataWithNextSmaller(this, this._left);
elementDeleted = _left.DeleteElement(data, out _left, out heightDecreased);
}
}
else
{
heightDecreased = false;
return(false);
}
if (heightDecreased && deletedLeft)
{
if (_balance == 0) // if an element is deleted on the left side, and the node was balanced the node is now taller on the right side
{ // but the overall height did not change
_balance = 1;
node = this;
heightDecreased = false;
}
else if (_balance > 0) // the right side was already taller; therefore we need to rearrange
{
if (_right._balance == 0) // the left subtree will be higher by one element
{
_right._balance = -1;
_balance = 1;
RotateRight(out node);
heightDecreased = false;
}
else if (_right._balance > 0) // the left subtree grows; therefore the overall size will shrink
{
_balance = 0;
_right._balance = 0;
RotateRight(out node);
heightDecreased = true;
}
else //(_right._balance < 0) // a double rotation is required
{
DoubleRotateRight(out node);
AdjustBalance(node);
heightDecreased = true;
}
}
else // the left subtree was higher; now left and right have the same hight
{
_balance = 0;
node = this;
heightDecreased = true;
}
}
else if (heightDecreased) // deleted right
{
if (_balance == 0) // if an element is deleted on the right side and the node was balanced, the node left subtree is now taller
{
_balance = -1;
node = this;
heightDecreased = false;
}
else if (_balance < 0) //the left subtree was taller; we need to rearrange
{
if (_left._balance == 0)
{
_left._balance = 1;
_balance = -1;
RotateLeft(out node);
heightDecreased = false;
}
else if (_left._balance < 0)
{
_balance = 0;
_left._balance = 0;
RotateLeft(out node);
heightDecreased = true;
}
else // left._balance > 0
{
DoubleRotateLeft(out node);
AdjustBalance(node);
heightDecreased = true;
}
}
else
{
_balance = 0;
node = this;
heightDecreased = true;
}
}
else // heigth of subtree did not change!
{
node = this;
heightDecreased = false;
}
return(elementDeleted);
}
private bool AddChildRight(T data, out LinkedAvlTreeNode <T> node, out bool added)
{
bool subTreeHeightIncreased = false;
if (_right == null)
{
LinkedAvlTreeNode <T> child = new LinkedAvlTreeNode <T>(data);
_right = child;
child._previous = this;
child._next = this._next;
if (this._next != null)
{
this._next._previous = child;
}
this._next = child;
added = true;
if (_balance == 0)
{
_balance = 1;
}
else
{
System.Diagnostics.Debug.Assert(_balance == -1);
_balance = 0;
}
node = this;
return(_balance != 0);
}
else
{
subTreeHeightIncreased = _right.AddData(data, out _right, out added);
}
if (!subTreeHeightIncreased)
{
node = this;
return(false);
}
// the subtree height has changed!
if (_balance < 0) // the tree is balanced in a way that it has more children that are smaller
{
_balance = 0; // now the tree is balanced
node = this;
return(false);
}
else if (_balance == 0)
{
_balance = 1; // the tree is now unbalanced but still ok
node = this;
return(true);
}
else //we have to reestablish the order criterion of the tree
{
if (_right._balance == 1) // single rotation
{
RotateRight(out node);
node._balance = 0;
_balance = 0;
}
else // double rotation
{
DoubleRotateRight(out node);
AdjustBalance(node);
}
return(false);
}
}
/// <summary>
/// add a child whose value is smaller than the current data item
/// </summary>
/// <param name="child"></param>
private bool AddChildLeft(T data, out LinkedAvlTreeNode <T> node, out bool added)
{
bool subTreeHeightIncreased = false;
if (_left == null) // there is no smaller subtree!
{
LinkedAvlTreeNode <T> child = new LinkedAvlTreeNode <T>(data);
_left = child;
child._next = this;
child._previous = this._previous;
if (this._previous != null)
{
this._previous._next = child;
}
this._previous = child;
node = this;
added = true;
if (_balance == 0) // if the tree was balanced before, it is now longer on the left side
{
_balance = -1;
}
else // if it was longer on the right side!
{
System.Diagnostics.Debug.Assert(_balance == 1);
_balance = 0;
}
return(_balance != 0);
}
else
{
subTreeHeightIncreased = _left.AddData(data, out _left, out added);
}
if (!subTreeHeightIncreased)
{
node = this;
return(false);
}
// the subtree height has changed!
if (_balance > 0) // the tree is balanced in a way that it has more children that are bigger
{
_balance = 0; // now the tree is balanced
node = this;
return(false);
}
else if (_balance == 0)
{
_balance = -1; // the tree is now unbalanced but still ok
node = this;
return(true);
}
else //we have to reestablish the order criterion of the tree
{
if (_left._balance == -1) // single rotation
{
_left._balance = 0;
_balance = 0;
RotateLeft(out node);
}
else // double rotation
{
DoubleRotateLeft(out node);
AdjustBalance(node);
}
return(false);
}
}
