Hacker Rank - Tree: Level Order Traversal Challenge https://www.hackerrank.com/challenges/tree-level-order-traversal/problem

Solution.java

import java.util.*;
import java.io.*;

class Solution {
  
  class Node {
    Node left;
    Node right;
    int data;
    
    Node(int data) {
        this.data = data;
        left = null;
        right = null;
    }
  }

	/* 
    
    class Node 
    	int data;
    	Node left;
    	Node right;
	*/
    public static void levelOrder(Node root) {
      
      
      if (root != null) {
          LinkedList<Node> q = new LinkedList<>();
          q.add(root);
          while (!q.isEmpty()) {
              Node curr = q.poll();
              if (curr.left != null) q.offer(curr.left);
              if (curr.right !=null) q.offer(curr.right);
            
              System.out.print(curr.data + " ");
          }
      }
      System.out.println();
      
    }

    public static Node insert(Node root, int data) {
        if(root == null) {
            return new Node(data);
        } else {
            Node cur;
            if(data <= root.data) {
                cur = insert(root.left, data);
                root.left = cur;
            } else {
                cur = insert(root.right, data);
                root.right = cur;
            }
            return root;
        }
    }

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int t = scan.nextInt();
        Node root = null;
        while(t-- > 0) {
            int data = scan.nextInt();
            root = insert(root, data);
        }
        scan.close();
        levelOrder(root);
    }	
}