public void TraversePostOrder(BTSNode parent)
{
if (parent != null)
{
TraversePostOrder(parent.LeftNode);
TraversePostOrder(parent.RightNode);
Console.Write(parent.Data + " ");
}
}
// Get the value of the left-most child node of this subtree.
private int MinValue(BTSNode node)
{
int minv = node.Data;
while (node.LeftNode != null)
{
minv = node.LeftNode.Data;
node = node.LeftNode;
}
return(minv);
}
public bool Add(int value)
{
BTSNode before = null, after = this.Root;
//Get the direct parent node for this value
while (after != null)
{
before = after;
if (value < after.Data) //Is new node in left tree?
{
after = after.LeftNode;
}
else if (value > after.Data) //Is new node in right tree?
{
after = after.RightNode;
}
else
{
//Same value already exists in the tree
return(false);
}
}
BTSNode newNode = new BTSNode();
newNode.Data = value;
if (this.Root == null) //Tree is empty
{
this.Root = newNode;
}
else
{
//Set value based on "before" we found above
if (value < before.Data)
{
before.LeftNode = newNode;
}
else
{
before.RightNode = newNode;
}
}
return(true);
}
// Recursively search through the tree
private BTSNode Find(int value, BTSNode parent)
{
if (parent != null)
{
if (value == parent.Data)
{
return(parent);
}
if (value < parent.Data)
{
return(Find(value, parent.LeftNode));
}
else
{
return(Find(value, parent.RightNode));
}
}
return(null);
}
private BTSNode Remove(BTSNode parent, int key)
{
if (parent == null)
{
return(parent);
}
if (key < parent.Data)
{
parent.LeftNode = Remove(parent.LeftNode, key);
}
else if (key > parent.Data)
{
parent.RightNode = Remove(parent.RightNode, key);
}
// If value is = to parent's value, then this (parent) is the node to be deleted
else
{
// We need to "shift up" all the children to remove this node.
// Node with only one child or no child
if (parent.LeftNode == null)
{
return(parent.RightNode);
}
else if (parent.RightNode == null)
{
return(parent.LeftNode);
}
// Node with two children: Get the inorder successor (smallest in the right subtree)
parent.Data = MinValue(parent.RightNode);
// Delete the inorder successor
parent.RightNode = Remove(parent.RightNode, parent.Data);
}
return(parent);
}
public static void BinarySearchTree_Main()
{
BinarySearchTree binaryTree = new BinarySearchTree();
binaryTree.Add(1);
binaryTree.Add(2);
binaryTree.Add(7);
binaryTree.Add(3);
binaryTree.Add(10);
binaryTree.Add(5);
binaryTree.Add(8);
// 1
/// \
// 2
// \
// 7
// / \
// 3 10
// \ /
// 5 8
BTSNode node = binaryTree.Find(5);
int depth = binaryTree.GetTreeDepth();
Console.WriteLine("PreOrder Traversal:");
binaryTree.TraversePreOrder(binaryTree.Root);
Console.WriteLine();
Console.WriteLine("InOrder Traversal:");
binaryTree.TraverseInOrder(binaryTree.Root);
Console.WriteLine();
Console.WriteLine("PostOrder Traversal:");
binaryTree.TraversePostOrder(binaryTree.Root);
Console.WriteLine();
binaryTree.Remove(7);
binaryTree.Remove(8);
// 1
/// \
// 2
// \
// 8
// / \
// 3 10
// \
// 5
// 1
/// \
// 2
// \
// 10
// /
// 3
// \
// 5
Console.WriteLine("PreOrder Traversal After Removing Operation:");
binaryTree.TraversePreOrder(binaryTree.Root);
Console.WriteLine();
Console.ReadLine();
}
private int GetTreeDepth(BTSNode parent)
{
return(parent == null ? 0 : Math.Max(GetTreeDepth(parent.LeftNode), GetTreeDepth(parent.RightNode)) + 1);
}
public void Remove(int value)
{
this.Root = Remove(this.Root, value);
}