public bool RotateLeft(AbstractNode <T> node)
{
/*
* z y
* / \ / \
* T1 y Left Rotate(z) z x
* / \ - - - - - - - -> / \ / \
* p x T1 p T3 T4
* / \
* T3 T4
*/
AvlTreeNode <T> z = (AvlTreeNode <T>)node;
AvlTreeNode <T> y = (AvlTreeNode <T>)node.Right;
AbstractNode <T> p = y.Left;
y.Ancestor = z.Ancestor;
z.Ancestor = y;
z.Right = p;
if (p != null)
{
p.Ancestor = z;
}
y.Left = z;
SetAncestor(y);
AdjustHeightToNode(z);
AdjustBalancefactorToNode(z);
AdjustHeightToNode(y);
AdjustBalancefactorToNode(y);
return(true);
}
private void AdjustHeights(AbstractNode <T> node, bool deletion)
{
AvlTreeNode <T> current = (AvlTreeNode <T>)node;
AvlTreeNode <T> leftNode = (AvlTreeNode <T>)current.Left;
AvlTreeNode <T> rightNode = (AvlTreeNode <T>)current.Right;
while (true)
{
int left = leftNode?.Height ?? 0;
int right = rightNode?.Height ?? 0;
current.Height = 1 + Math.Max(left, right);
current.BalanceFactor = left - right;
if (deletion && (current.BalanceFactor > 1 || current.BalanceFactor < -1))
{
Rebalance(current);
}
if (current.Ancestor == null)
{
return;
}
current = (AvlTreeNode <T>)current.Ancestor;
leftNode = (AvlTreeNode <T>)current.Left;
rightNode = (AvlTreeNode <T>)current.Right;
}
}
private static void CheckResultAfterDeletion(AvlTreeNode root)
{
AssertTrue(() => root.Value == 1);
AssertTrue(() => root.Left.Value == 0);
AssertTrue(() => root.Left.Right == null);
AssertTrue(() => root.Left.Left.Value == -1);
AssertTrue(() => root.Left.Left.Right == null);
AssertTrue(() => root.Left.Left.Left == null);
AssertTrue(() => root.Right.Value == 9);
AssertTrue(() => root.Right.Left.Value == 5);
AssertTrue(() => root.Right.Right.Value == 11);
AssertTrue(() => root.Right.Right.Left == null);
AssertTrue(() => root.Right.Right.Right == null);
AssertTrue(() => root.Right.Left.Right.Value == 6);
AssertTrue(() => root.Right.Left.Right.Left == null);
AssertTrue(() => root.Right.Left.Right.Right == null);
AssertTrue(() => root.Right.Left.Left.Value == 2);
AssertTrue(() => root.Right.Left.Left.Left == null);
AssertTrue(() => root.Right.Left.Left.Right == null);
}
private int ValidateHeight(AvlTreeNode <T> node)
{
if (node == null)
{
return(0);
}
return(node.GetHeight());
}
private AvlTreeNode <T> FindMin(AvlTreeNode <T> node)
{
if (node.GetLeft() == null)
{
return(node);
}
return(FindMin(node.GetLeft()));
}
private static int Height <T>(AvlTreeNode <T> node, int deep)
{
var leftHeight = node.Left != null?Height(node.Left, deep + 1) : 0;
var rightHeight = node.Right != null?Height(node.Right, deep + 1) : 0;
return((leftHeight > rightHeight ? leftHeight : rightHeight) + 1);
}
public void Key_Setter_StoresTheValue()
{
var instance = new AvlTreeNode <int, string> {
Key = 100
};
Assert.AreEqual(100, instance.Key);
}
public void Balance_Setter_StoresTheValue()
{
var instance = new AvlTreeNode <int, string> {
Balance = -1
};
Assert.AreEqual(-1, instance.Balance);
}
public void Value_Setter_StoresTheValue()
{
var instance = new AvlTreeNode <int, string> {
Value = "Hello"
};
Assert.AreEqual("Hello", instance.Value);
}
public void MaxHeightTest_RootLeft()
{
var t = new AvlTreeNode(5)
{
Left = new AvlTreeNode(4)
};
Assert.AreEqual(1, t.MaxHeight);
}
public void MaxHeightTest_RootRight()
{
var t = new AvlTreeNode(5)
{
Right = new AvlTreeNode(6)
};
Assert.AreEqual(1, t.MaxHeight);
}
public void MaxHeightTest_RootTwoChildren()
{
var t = new AvlTreeNode(5)
{
Left = new AvlTreeNode(4), Right = new AvlTreeNode(6)
};
Assert.AreEqual(1, t.MaxHeight);
}
public void BalanceTest_RootLeft()
{
var t = new AvlTreeNode(5)
{
Left = new AvlTreeNode(4)
};
Assert.AreEqual(-1, t.Balance);
}
public void BalanceTest_RootRight()
{
var t = new AvlTreeNode(5)
{
Right = new AvlTreeNode(6)
};
Assert.AreEqual(1, t.Balance);
}
public void BalanceTestTest_RootTwoChildren()
{
var t = new AvlTreeNode(5)
{
Left = new AvlTreeNode(4), Right = new AvlTreeNode(6)
};
Assert.AreEqual(0, t.Balance);
}
public void RightChild_Setter_StoresTheValue()
{
var r = new AvlTreeNode <int, string>();
var instance = new AvlTreeNode <int, string> {
RightChild = r
};
Assert.AreSame(r, instance.RightChild);
}
private static int Count <T>(AvlTreeNode <T>?node)
{
if (node == null)
{
return(0);
}
var count = 1 + Count(node.Left) + Count(node.Right);
return(count);
}
private void AdjustBalancefactorToNode(AvlTreeNode <T> node)
{
AvlTreeNode <T> current = (AvlTreeNode <T>)node;
AvlTreeNode <T> leftNode = (AvlTreeNode <T>)current.Left;
AvlTreeNode <T> rightNode = (AvlTreeNode <T>)current.Right;
int left = leftNode?.Height ?? 0;
int right = rightNode?.Height ?? 0;
current.BalanceFactor = left - right;
}
private void AdjustHeightToNode(AvlTreeNode <T> node)
{
AvlTreeNode <T> current = (AvlTreeNode <T>)node;
AvlTreeNode <T> leftNode = (AvlTreeNode <T>)current.Left;
AvlTreeNode <T> rightNode = (AvlTreeNode <T>)current.Right;
int left = leftNode?.Height ?? 0;
int right = rightNode?.Height ?? 0;
current.Height = 1 + Math.Max(left, right);
}
private int GetBalanceFactor(AvlTreeNode <T> node)
{
AvlTreeNode <T> current = (AvlTreeNode <T>)node;
AvlTreeNode <T> leftNode = (AvlTreeNode <T>)current.Left;
AvlTreeNode <T> rightNode = (AvlTreeNode <T>)current.Right;
int left = leftNode?.Height ?? 0;
int right = rightNode?.Height ?? 0;
return(left - right);
}
public string[] ShowAllBooksArray(string libraryName)
{
Library l = new Library(libraryName);
AvlTreeNode <Library> lib = (AvlTreeNode <Library>)LibraryModel.Libraries.SearchNode(l, LibraryModel.Libraries.Root);
if (lib != null && lib.Data.AllBooksByName != null)
{
return(lib.Data.AllBooksByName.InorderTraversalToStringArray(lib.Data.AllBooksByName.Root));
}
return(new string[] {});
}
public void BalanceFactorTest()
{
AvlTree <int> actual = new AvlTree <int> {
10, 20
};
AvlTreeNode <int> root = actual.FindNode(10);
AvlTreeNode <int> leaf = actual.FindNode(20);
AvlTreeNode <int> emptyNode = default(AvlTreeNode <int>);
Assert.AreEqual(actual.GetBalanceFactor(root), -1);
Assert.AreEqual(actual.GetBalanceFactor(leaf), 0);
Assert.AreEqual(actual.GetBalanceFactor(emptyNode), 0);
}
public bool ArchiveBook(string isbn, int bookId, string libraryName)
{
Book b = new Book(isbn, bookId, "");
AvlTreeNode <Library> lib = (AvlTreeNode <Library>)LibraryModel.Libraries.SearchNode(new Library(libraryName), LibraryModel.Libraries.Root);
AbstractNode <Book> foundB = lib.Data.AllBooksByIsbn.SearchNode(b, lib.Data.AllBooksByIsbn.Root);
if (foundB != null)
{
foundB.Data.IsArchived = true;
return(foundB.Data.IsArchived);
}
return(false);
}
private AvlTreeNode <T> Balance(AvlTreeNode <T> node)
{
if (node == null)
{
return(null);
}
int balance = ValidateHeight(node.GetLeft())
- ValidateHeight(node.GetRight());
if (balance == 2)
{
if (node.GetLeft().GetLeft() != null)
{
if (node == _root)
{
_root = node.GetLeft();
}
node = node.RotateLeftChild();
}
else
{
if (node == _root)
{
_root = node.GetLeft().GetRight();
}
node = node.RotateDoubleLeft();
}
}
else if (balance == -2)
{
if (node.GetRight().GetRight() != null)
{
if (node == _root)
{
_root = node.GetRight();
}
node = node.RotateRightChild();
}
else
{
if (node == _root)
{
_root = node.GetRight().GetLeft();
}
node = node.RotateDoubleRight();
}
}
node.CalculateHeight();
return(node);
}
private bool Rebalance(AvlTreeNode <T> nodeToRebalance)
{
AvlTreeNode <T> node = (AvlTreeNode <T>)nodeToRebalance;
AvlTreeNode <T> right = (AvlTreeNode <T>)node.Right;
AvlTreeNode <T> left = (AvlTreeNode <T>)node.Left;
bool loop = true;
while (loop)
{
// Left left case || Left right case
if (node.BalanceFactor == 2)
{
// left left case
if (left.BalanceFactor >= 0)
{
return(RotateRight(node));
}
// left right case
if (left.BalanceFactor < 0)
{
return(RotateLeftRight(node));
}
}
// Right right case || right left case
if (node.BalanceFactor == -2)
{
// Right right case
if (right.BalanceFactor <= 0)
{
return(RotateLeft(node));
}
// Right left case
if (right.BalanceFactor > 0)
{
return(RotateRightLeft(node));
}
}
if (node.Ancestor == null)
{
loop = false;
}
else
{
node = (AvlTreeNode <T>)node.Ancestor;
right = (AvlTreeNode <T>)node.Right;
left = (AvlTreeNode <T>)node.Left;
}
}
return(true);
}
public bool Add(AvlTreeNode <T> node)
{
if (Root == null)
{
Root = node;
}
else
{
InsertNode(Root, node.Data, node);
}
AdjustHeightToNode(Root);
AdjustBalancefactorToNode(Root);
return(true);
}
public void MaxHeightTest()
{
var t = new AvlTreeNode(5)
{
Left = new AvlTreeNode(3)
{
Left = new AvlTreeNode(2),
Right = new AvlTreeNode(4)
},
Right = new AvlTreeNode(6)
};
Assert.AreEqual(2, t.MaxHeight);
}
public void BalanceTest()
{
var t = new AvlTreeNode(5)
{
Left = new AvlTreeNode(3)
{
Left = new AvlTreeNode(2),
Right = new AvlTreeNode(4)
},
Right = new AvlTreeNode(6)
};
Assert.AreEqual(-1, t.Balance);
}
private bool InsertNode(AbstractNode <T> current, T data, AvlTreeNode <T> node)
{
AvlTreeNode <T> inserted = node;
while (true)
{
//if (inserted.Data.CompareTo(current.Data) == 0)
if (Comparer.Compare(data, current.Data) == 0)
{
return(false);
}
else if (Comparer.Compare(inserted.Data, current.Data) == -1)
{
if (current.Left == null)
{
current.Left = inserted;
inserted.Ancestor = current;
// upravit vysky
AdjustHeights(inserted, false);
// upravit balance factor
//AdjustBalanceFactor(inserted);
Rebalance((AvlTreeNode <T>)inserted.Ancestor);
return(true);
}
else
{
current = current.Left;
}
}
else
{
if (current.Right == null)
{
current.Right = inserted;
inserted.Ancestor = current;
// upravit vysky
AdjustHeights(inserted, false);
// upravit balance factor
//AdjustBalanceFactor(inserted);
Rebalance((AvlTreeNode <T>)inserted.Ancestor);
return(true);
}
else
{
current = current.Right;
}
}
}
}
private AvlTreeNode <T> SearchRecursive(T value, AvlTreeNode <T> node)
{
if (node == null)
{
return(null);
}
if (node.GetValue().CompareTo(value) > 0)
{
return(SearchRecursive(value, node.GetLeft()));
}
if (node.GetValue().CompareTo(value) < 0)
{
return(SearchRecursive(value, node.GetRight()));
}
return(node);
}
public void HeightTest()
{
AvlTreeNode<int> actual = new AvlTreeNode<int>(20);
Assert.AreEqual(1, actual.Height);
}
public void HeightPUT(int value)
{
AvlTreeNode<int> actual = new AvlTreeNode<int>(value);
PexAssert.AreEqual(1, actual.Height);
}