Answer Happy

public class BinarySearchTree {
class Node {
int key;
Node left, right;
public Node(int item)
{
key = item;
left = right = null;
}
}
// Root of BST
Node root;
// Constructor
BinarySearchTree() { root = null; }
BinarySearchTree(int value) { root = new Node(value); }
// This method mainly calls insertRec()
void insert(int key) { root = insertRec(root, key); }
/* A recursive function to
insert a new key in BST */
Node insertRec(Node root, int key)
{
/* If the tree is empty,
return a new node */
if (root == null) {
root = new Node(key);
return root;
}
/* Otherwise, recur down the tree */
if (key < root.key)
root.left = insertRec(root.left, key);
else if (key > root.key)
root.right = insertRec(root.right, key);
else if (key > root.key)
root.left.left = insertRec(root.left.left, key);
/* return the (unchanged) node pointer */
return root;
}
// This method mainly calls InorderRec()
void preorder() { preorderRec(root); } // Inorder recursive
function
// A utility function to
// do inorder traversal of BST
void preorderRec(Node root)
{
if (root != null) {
preorderRec(root.left);
System.out.println(root.key);
preorderRec(root.right);
}
}
// Driver Code
public static void main(String[] args)
{
BinarySearchTree tree = new BinarySearchTree();
tree.insert(20);
tree.insert(30);
tree.insert(50);
tree.insert(40);
tree.insert(100);
tree.insert(60);
tree.insert(80);
tree.insert(70); // print preorder traversal of the BST
tree.preorder();
}
}