class BST_class {
//node class that defines BST node
class Node {
int key;
Node left, right;
public Node(int data){
key = data;
left = right = null;
}
}
// BST root node
Node root;
// Constructor for BST =>initial empty tree
BST_class(){
root = null;
}
//delete a node from BST
void deleteKey(int key) {
root = delete_Recursive(root, key);
}
//recursive delete function
Node delete_Recursive(Node root, int key) {
//tree is empty
if (root == null) return root;
//traverse the tree
if (key < root.key) //traverse left subtree
root.left = delete_Recursive(root.left, key);
else if (key > root.key) //traverse right subtree
root.right = delete_Recursive(root.right, key);
else {
// node contains only one child
if (root.left == null)
return root.right;
else if (root.right == null)
return root.left;
// node has two children;
//get inorder successor (min value in the right subtree)
root.key = minValue(root.right);
// Delete the inorder successor
root.right = delete_Recursive(root.right, root.key);
}
return root;
}
int minValue(Node root) {
//initially minval = root
int minval = root.key;
//find minval
while (root.left != null) {
minval = root.left.key;
root = root.left;
}
return minval;
}
// insert a node in BST
void insert(int key) {
root = insert_Recursive(root, key);
}
//recursive insert function
Node insert_Recursive(Node root, int key) {
//tree is empty
if (root == null) {
root = new Node(key);
return root;
}
//traverse the tree
if (key < root.key) //insert in the left subtree
root.left = insert_Recursive(root.left, key);
else if (key > root.key) //insert in the right subtree
root.right = insert_Recursive(root.right, key);
// return pointer
return root;
}
// method for inorder traversal of BST
void inorder() {
inorder_Recursive(root);
}
// recursively traverse the BST
void inorder_Recursive(Node root) {
if (root != null) {
inorder_Recursive(root.left);
System.out.print(root.key + " ");
inorder_Recursive(root.right);
}
}
boolean search(int key) {
root = search_Recursive(root, key);
if (root!= null)
return true;
else
return false;
}
//recursive insert function
Node search_Recursive(Node root, int key) {
// Base Cases: root is null or key is present at root
if (root==null || root.key==key)
return root;
// val is greater than root\'s key
if (root.key > key)
return search_Recursive(root.left, key);
// val is less than root\'s key
return search_Recursive(root.right, key);
}
}