# Coding Challenge Day-16: Problem 1: Deleting leaf node in a Binary Search Tree

Hello! So I’m doing a 30 day coding challenge where I solve a few questions every day and thought of posting them here on my blog so that you guys can join the challenge too!

Welcome to Coding challenge Day 16: Problem 1! Be sure to post your answers, queries etc in the comments!

Problem: Deleting leaf node (node with no children) in a Binary Search Tree

Sample: Element to be deleted= 7

Tree before deleting element:

Tree after deleting element:

Output:

Original Tree
3 4 5 6 7 8 9 10 11
Tree after deleting element 7
3 4 5 6 8 9 10 11

Solution:

``````package tree.binarysearchtree;

public class Program003delete_leaf_node {

static class Node {
int data;
Node left, right;

public Node (int d){
data=d;
left= right=null;
}
}

static class BST {
Node root;

public BST(){
root= null;
}

public void add_left(Node parent_node, Node node){
parent_node.left= node;
}

public void add_right(Node parent_node, Node node){
parent_node.right= node;
}

public void inorder_traversal (Node node){
if(node==null){
return;
}

inorder_traversal(node.left);
System.out.print(node.data + " ");
inorder_traversal(node.right);
}

public void delete_leaf_node (Node node, int element){
if(node==null){
return;
}

if(node.left!= null && (node.left).data==element){
node.left=null;
return;
}

if(node.right!=null &&(node.right).data==element){
node.right=null;
return;
}

if(element<node.data){
delete_leaf_node(node.left, element);
}

if(element>node.data){
delete_leaf_node(node.right, element);
}

}

}

public static void main (String [] args){
BST tree= new BST();

tree.root= new Node(8);

Node node6= new Node(6);

Node node10= new Node(10);

Node node4= new Node(4);

Node node7= new Node(7);

Node node9= new Node(9);

Node node11= new Node(11);

Node node3= new Node(3);

Node node5= new Node(5);

int delete_element= 7;

System.out.println("Original Tree");
tree.inorder_traversal(tree.root);
tree.delete_leaf_node(tree.root, delete_element);
System.out.println();
System.out.println("Tree after deleting element " + delete_element);
tree.inorder_traversal(tree.root);
}

}
``````