BreadthFirst.java

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

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

class Solution {
	
	static void levelOrder(Node root) {
		Queue<Node> nodeQueue = new LinkedList<>();
		nodeQueue.add(root);
		
		
		while (!nodeQueue.isEmpty()) {
			Node myNode = nodeQueue.remove();
			System.out.printf("%d ", myNode.data);
			if (null != myNode.left) {
				nodeQueue.add(myNode.left);
			}
			if (null != myNode.right) {
				nodeQueue.add(myNode.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);
	}
}