public UndirectedGraphNode searchNode(ArrayList<UndirectedGraphNode> graph,
                                          Map<UndirectedGraphNode, Integer> values,
                                          UndirectedGraphNode node,
                                          int target) {
        // Write your code here
        HashMap<UndirectedGraphNode, Integer> map = new HashMap<>();
        Queue<UndirectedGraphNode> q = new LinkedList<UndirectedGraphNode>();
        q.add(node);
        map.put(node, node.label);

        while (!q.isEmpty()) {
            UndirectedGraphNode tmp = q.poll();

            if (values.get(tmp) == target) {
                return tmp;
            }
            for (UndirectedGraphNode neig : tmp.neighbors) {
                if (!map.containsKey(neig)) {
                 q.add(neig);
                map.put(neig, neig.label);
                }
            }
        }
        return null;
    }