import java.util.*;

class Tree

{

//Runs in O(V+E) time and O(V) Space

public static ArrayList<Character> breadthFirstSearch(Node root)

{

Queue<Character> q = new LinkedList<Character>();

q.add(root);

ArrayList<Character> LOTraversal = new ArrayList<Character>();

while(!q.isEmpty())

{

Node current = q.poll();

LOTraversal.add(root.data);

//add the all childs of current node to queue

// q.add(all childs of current node)

}

return LOTraversal;

}

class Node

{

public Node(char data)

{

char data;

ArrayList<Character> childs = new ArrayList<Character>();

}

}

Node root;

public static void add(Node root,Node addingPosition,char value)

{

if(root == null)

{

root = new Node(value);

return;

}

}

public static void main(String[] args)

{

//pass a graph/tree as argument where nodes are named as charcters

ArrayList<Character> al = breadthFirstSearch(root);

System.out.println(al.toString()); //PRints the array List Level order traversal

}

}