public static <T> void print_binary_tree_level_order(BinarySearchTree<T> n) {
        // Prevent empty tree
        if(n == null) {
            return;
        }

        LinkedList<BinarySearchTree<T>> q = new LinkedList<BinarySearchTree<T>>();
        q.push(n);
        int count = q.size();
        while(!q.isEmpty()) {
            BinarySearchTree<T> front = q.pollLast();
            System.out.print(front.getData() + " ");
            if(front.getLeft() != null) {
                q.push(front.getLeft());
            }
            if(front.getRight() != null) {
                q.push(front.getRight());
            }
            if(--count == 0) {
                System.out.println();
                count = q.size();
            }
        }
    }