Level Order in spiral form

import java.util.*;

class Solution {
    public ArrayList<Integer> findSpiral(Node root) {
        ArrayList<Integer> res = new ArrayList<>();
        if (root == null)
            return res;

        Queue<Node> q = new LinkedList<>();
        q.offer(root);
        boolean leftToRight = false;

        while (!q.isEmpty()) {
            int size = q.size();
            ArrayList<Integer> levelList = new ArrayList<>();

            for (int i = 0; i < size; i++) {
                Node node = q.poll();
                levelList.add(node.data);

                if (node.left != null)
                    q.offer(node.left);
                if (node.right != null)
                    q.offer(node.right);
            }

            if (leftToRight)
                res.addAll(levelList);
            else {
                for (int i = levelList.size() - 1; i >= 0; i--)
                    res.add(levelList.get(i));
            }

            leftToRight = !leftToRight;
        }

        return res;
    }
}

class Node {
    int data;
    Node left, right;

    Node(int item) {
        data = item;
        left = right = null;
    }
}