public static List<Node> sortedTopology(Graph graph) {
        //<某个Node,剩余的入度>
        Map<Node, Integer> inMap = new HashMap<>();
        //剩余入度为0的点，才能进这个队列
        Deque<Node> zeroInQueue = new LinkedList<>();

        for (Node node : graph.nodes.values()) {
            inMap.put(node, node.in);
            if (node.in == 0) {
                zeroInQueue.add(node);
            }
        }

        List<Node> res = new ArrayList<>();
        while (!zeroInQueue.isEmpty()) {
            Node poll = zeroInQueue.poll();
            res.add(poll);
            //消除删掉节点的影响
            for (Node next : poll.nexts) {
                inMap.put(next, inMap.get(next) - 1);
                if (inMap.get(next) == 0) {
                    zeroInQueue.add(next);
                }
            }
        }
        return res;
    }