width bt java

// http://code2begin.blogspot.com
// program to print width of a given binary tree

/**
 * Created by MOHIT on 25-05-2018.
 */
import java.util.*;

// 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 the width of the binary tree
    static int width(node root){
        if(root == null){
            return 0 ;
        }

        // creating a Queue for storing node for level wise traversal
        ArrayList Q = new ArrayList<node>();
        Q.add(root);
        int result = 0;

        while(!Q.isEmpty()){
            // store the current size of the Q
            int count = Q.size();

            // find out the max width
            result = max(result, count);

            while(count > 0) {
                // pop the first node from the queue
                node Node = (node)Q.get(0);
                Q.remove(0);

                // push the left child on queue
                if (Node.left != null) {
                    Q.add(Node.left);
                }

                // push the right child on queue
                if (Node.right != null) {
                    Q.add(Node.right);
                }
                count -= 1;
            }
        }

        // return the final width
        return result;
    }

    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("Width of the above binary tree is : " + width(head));

    }
}