如果有人可以幫助我完成此任務，我將不勝感激。任務：實現一個Graph類（有向和加權），而無需使用Java的標準Graph-class。使用adjacencyList或adjMatrix都沒關系我的密碼import java.util.*;public class Graph {    static class Edge {        char vA;        char vB;        double weight;        Edge(char a, char b, double weight) {            vA = a;            vB = b;            this.weight = weight;        }        void setWeight(double w) {            weight = w;        }        double getWeight() {            return weight;        }    }    private Map<Character, LinkedList<Character>> edges = new HashMap<>();    void addNode(char node) {        if (!edges.containsKey(node)) {            edges.put(node, new LinkedList<Character>());        }    }    public void addEdge(char a, char b, double weight) {        Edge e = new Edge(a, b, weight);        a = e.vA;        b = e.vB;        e.setWeight(weight);        edges.get(a).add(b);    }    void printNodes() {        System.out.println(edges.keySet());    }    void printEdges() {        System.out.println(edges.values());    }    void dfs() {        //TODO    }    void dijkstra(char startNodeID){    }    public static void main(String... args) {        Graph graph = new Graph();        graph.addNode('A');        graph.addNode('B');        graph.addNode('C');        graph.addNode('D');        graph.addNode('E');        graph.addEdge('A', 'B', 2);        graph.addEdge('A', 'C', 3);        graph.addEdge('B', 'D', 6);        graph.addEdge('C', 'D', 8);        graph.addEdge('C', 'E', 9);        graph.printEdges();        graph.printNodes();    }}問題：如何在EdgeMap的LinkedList中添加邊？我的方法addEdges有什么問題？如何打印邊緣？