## 圖的Java數據結構 圖的2要素：頂點集合和邊集合 ~~~ public class Graph { // 頂點集 - 鄰接表 public HashMap<String,Vertex> vertexs; // 邊集 public Set<Edge> edges; public Graph() { this.vertexs = new HashMap<>(); this.edges = new HashSet<>(); } } ~~~ ~~~ // 頂點 class Vertex{ // 名稱，值 public String value; // 入度 public Integer in; // 出度 public Integer out; // 相鄰的頂點集合 public Set<Vertex> nexts; // 邊集合 public Set<Edge> edges; public Vertex(String value) { this.value = value; this.in = 0; this.out = 0; this.nexts = new HashSet<>(); this.edges = new HashSet<>(); } } ~~~ ~~~ // 邊 class Edge{ // 權重 public int weight; // 出發頂點 public Vertex from; // 到達頂點 public Vertex to; public Edge(int weight, Vertex from, Vertex to) { this.weight = weight; this.from = from; this.to = to; } } ~~~