数据结构-Java实现简单的有向图及无向图结构Graph

import java.util.HashMap; import java.util.HashSet; import java.util.Map; import java.util.Set; public class Graph1<T> { private final Map<T, Set<T>> nodes; public Graph1() { nodes = new HashMap<>(); } public void addNode(T node) { nodes.putIfAbsent(node, new HashSet<>()); } public void addEdge(T from, T to) { nodes.computeIfAbsent(from, k -> new HashSet<>()).add(to); nodes.computeIfAbsent(to, k -> new HashSet<>()).add(from); } public Set<T> getNeighbors(T node) { return nodes.getOrDefault(node, new HashSet<>()); } public Set<T> getNodes() { return new HashSet<>(nodes.keySet()); } public static void main(String[] args) { Graph1<String> graph = new Graph1<>(); // 添加节点 graph.addNode("A"); graph.addNode("B"); graph.addNode("C"); // 添加边 graph.addEdge("A", "B"); graph.addEdge("A", "C"); graph.addEdge("B", "C"); // 获取节点的邻居 System.out.println(graph.getNeighbors("A")); // 输出：[B, C] System.out.println(graph.getNeighbors("B")); // 输出：[A, C] System.out.println(graph.getNeighbors("C")); // 输出：[A, B] // 获取图中的所有节点 System.out.println(graph.getNodes()); // 输出：[A, B, C] } }