VerticalOrderTraversal-2

class Q
{
    int hd;
    Node temp;
    Q(Node t, int h)
    {
        temp = t;
        hd = h;
    }
}
class BinaryTree
{
    static int min = Integer.MAX_VALUE, max = Integer.MIN_VALUE;
    static void findVerticalOrder(Node root, HashMap<Integer, ArrayList<Integer>> hm)
    {
        if(root == null)
            return;
        Queue<Q> q = new LinkedList<Q>();
        q.add(new Q(root, 0));
        
        while(!q.isEmpty())
        {
            Q obj = q.pop();
            ArrayList<Integer> al = hm.get(obj.hd);
            if(al == null)
                al = new ArrayList<Integer>();
            al.add(obj.temp.data);
            hm.put(obj.hd, al);
            
            if(obj.temp.left != null)
                q.add(new Q(obj.temp.left, obj.hd-1));
            if(obj.temp.right != null)
                q.add(new Q(obj.temp.right, obj.hd+1));
            if(obj.hd < min)
                min = obj.hd;
            if(obj.hd > max)
                max = obj.hd;
        }
    }
    static void verticalOrder(Node root)
    {
        HashMap<Integer, ArrayList<Integer>> hm = new HashMap<Integer, ArrayList<Integer>>();
        int hd = 0;
        
        findVerticalOrder(root, hm);
        
        for(int i=min ; i<=max ; i++)
        {
            ArrayList<Integer> al = hm.get(i);
            if(al == null)
                continue;
            for(int j=0 ; j<al.size() ; j++)
                System.out.print(al.get(j) + " ");
        }
    }
}