day-23-bst-level-order-traversal.java

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

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

class Solution {

    static void levelOrder(Node root) {
        LinkedList<Node> queue = new LinkedList<Node>();
        queue.add(root);
        while (!queue.isEmpty()) {
            Node current = queue.poll();
            System.out.printf("%d ", current.data);
            if (current.left != null) {
                queue.add(current.left);
            }
            if (current.right != null) {
                queue.add(current.right);
            }
        } 
    }

    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 sc=new Scanner(System.in);
        int T=sc.nextInt();
        Node root=null;
        while(T-->0) {
            int data=sc.nextInt();
            root=insert(root,data);
        }
        levelOrder(root);
    }	
}