public bool IsBST(BTNode root)
{
return(IsBST(root, int.MinValue, int.MaxValue));
}
public bool InsertWithRecursion(BTNode node)
{
return(InsertWithRecursion(node, this.root));
}
/*
* Delete a Node in Binary Search tree. There can be three cases
* Case A: Node has no child, it is a leaf node. P.LChild = null OR P.Rchild = null
* Case B: Node has exactly one child.
* If node to be deleted is left child node of it's parent node. Then, child node of deleted node will become
* the left child of the parent. Similar for right child as well. If deleted node is root node then child node will become root node.
* Case C: Node has exactly two children.
* Find the inorder successor of the node to be deleted.
* Inorder successor of a node N : leftmost node in right subtree of N.
* After find the inorder successor copy the data of inorder successor to the node to be deleted.
* Then,delete the inorder successor from the tree.
*
*
*
*
*/
public bool Remove(char x)
{
BTNode p = this.root;
BTNode parent = null;
while (p != null)
{
if (x < p.value)
{
parent = p;
p = p.lChild;
}
else if (x > p.value)
{
parent = p;
p = p.rChild;
}
else
{
break;
}
}
if (p == null)
{
Console.WriteLine("Node is not present in the tree.");
return(false);
}
//Node to be deleted is root node
if (parent == null)
{
if (p.lChild != null & p.rChild != null)
{
BTNode p1 = p.rChild;
BTNode p1Parent = null;
while (p1.lChild != null)
{
p1Parent = p1;
p1 = p1.lChild;
}
p.value = p1.value;
p1Parent.lChild = p1.rChild;
}
else if (p.lChild != null && p.rChild == null)
{
this.root = p.lChild;
p = null;
}
else if (p.lChild == null && p.rChild != null)
{
this.root = p.rChild;
p = null;
}
else
{
p = null;
}
}
else
{
if (p.lChild != null & p.rChild != null)
{
BTNode p1 = p.rChild;
BTNode p1Parent = null;
while (p1.lChild != null)
{
p1Parent = p1;
p1 = p1.lChild;
}
p.value = p1.value;
p1Parent.lChild = p1.rChild;
}
else if (p.lChild != null && p.rChild == null)
{
if (parent.rChild == p)
{
parent.rChild = p.lChild;
}
else
{
parent.lChild = p.lChild;
}
p = null;
}
else if (p.lChild == null && p.rChild != null)
{
if (parent.rChild == p)
{
parent.rChild = p.rChild;
}
else
{
parent.lChild = p.rChild;
}
p = null;
}
else
{
p = null;
}
}
return(false);
}
public BinarySearchTree()
{
this.root = null;
}
