如何在给定代码的情况下打印广度第一次横移的结果(Java)

import java.util.*;

public class BFSExample {

    public static void main(String[] args) {
        // 给定的代码，构建图结构
        Map<String, List<String>> graph = new HashMap<>();
        graph.put("A", Arrays.asList("B", "C"));
        graph.put("B", Arrays.asList("D"));
        graph.put("C", Arrays.asList("E"));
        graph.put("D", Arrays.asList("F"));
        graph.put("E", Arrays.asList("G"));
        graph.put("F", Arrays.asList());
        graph.put("G", Arrays.asList());

        // 调用广度优先搜索算法打印结果
        bfs(graph, "A");
    }

    public static void bfs(Map<String, List<String>> graph, String start) {
        Queue<String> queue = new LinkedList<>();
        Set<String> visited = new HashSet<>();
        queue.add(start);
        visited.add(start);

        while (!queue.isEmpty()) {
            String node = queue.poll();
            System.out.print(node + " ");

            List<String> neighbors = graph.get(node);
            for (String neighbor : neighbors) {
                if (!visited.contains(neighbor)) {
                    queue.add(neighbor);
                    visited.add(neighbor);
                }
            }
        }
    }
}