Clone graph

LC133 Given a reference of a node in a connected undirected graph, return a deep copy (clone) of the graph. Each node in the graph contains a val (int) and a list (List[Node]) of its neighbors. O(V+E) E*V

class Node {
    public int val;
    public List<Node> neighbors;

    public Node() {}

    public Node(int _val,List<Node> _neighbors) {
        val = _val;
        neighbors = _neighbors;
    }
};

class Solution {
    public Node cloneGraph(Node node) {
        if (node == null) return node;
        Map<Node,Node> map = new HashMap<>();
        map.put(node, new Node(node.val, new ArrayList<Node>()));
        Queue<Node> queue = new LinkedList<>();
        queue.add(node);
        while(!queue.isEmpty()) {
            Node cur = queue.poll();
            for (Node neighbor: cur.neighbors) {
                if(!map.containsKey(neighbor)) {
                   queue.add(neighbor); 
                }
                Node nCopy = map.getOrDefault(neighbor, new Node(neighbor.val, new ArrayList<>()));
                map.get(cur).neighbors.add(nCopy);
                //nCopy.neighbors.add(map.get(cur));
                map.put(neighbor, nCopy);
            }
        }
        return map.get(node);
    }
}