nodes at k java

// http://code2begin.blogspot.com
// program to print nodes at a distance K from a given node in binary tree

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

import java.io.*;
import java.lang.reflect.Array;
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 {
    // function to print child nodes at a distance k from the given node
    static void print_nodes_at_K(node root, int K){
        if(root == null || K < 0){
            return;
        }
        if(K == 0){
            System.out.print(root.data + " ");
        }
        if(K > -1) {
            print_nodes_at_K(root.left, K - 1);
            print_nodes_at_K(root.right, K - 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.print("Nodes at distance 2 from the root node are : ");
        print_nodes_at_K(head, 2);
    }
}