deepest leaf java

// http://code2begin.blogspot.com
// program to find the deepest leaf node in a given binary tree

/**
 * Created by MOHIT on 25-05-2018.
 */

import java.io.*;
import java.util.*;
import static java.lang.Integer.max;


// node class
class node{
    int data;
    node left;
    node right;

    // function that returns a pointer to new node
    public node(int element){
        this.data = element;
        this.left = null;
        this.right = null;

    }
};


public class BinaryTree {

    static int max_level = -1;
    static int deepest_leaf = -9999;

    static int deepest_level_leaf_node(node root){
        max_level = -1;
        deepest_leaf = -9999;
        deepest_level_leaf_node_helper(root, -1);
        return deepest_leaf;
    }

    // function to print the deepest leaf node in the binary tree using inorder traversal method
    static void deepest_level_leaf_node_helper(node root, int level){
        // if the tree is empty or if we reach a leaf node then return 0
        if (root == null){
            return;
        }
        // check in the left subtree for the element
        // if found then return the level
        deepest_level_leaf_node_helper(root.left, level + 1);
        if(root.left == null && root.right == null && max_level < level){
            max_level = max(max_level, level);
            deepest_leaf = root.data;
        }
        deepest_level_leaf_node_helper(root.right, level + 1);
    }


    public static void main(String arg[]) {
        node head = new node(1);
        head.left = new node(2);
        head.right = new node(3);
        head.left.left = new node(4);
        head.left.right = new node(5);
        head.right.right = new node(6);
        head.left.left.right = new node(7);
        head.right.right.left = new node(8);
        head.left.left.right.left = new node(9);
        head.left.left.right.left.left = new node(10);
        head.right.right.left.right = new node(11);
        System.out.println("Deepest Level leaf node in the above binary tree is : " + deepest_level_leaf_node(head));

    }
}