jGraphT - 移除一个顶点并重新连接所有与被移除顶点相连的顶点

要使用jGraphT库移除一个顶点并重新连接所有与被移除顶点相连的顶点，可以按照以下步骤进行操作：

1. 创建有向图或无向图对象：

Graph<String, DefaultEdge> graph = new DefaultDirectedGraph<>(DefaultEdge.class);

或

Graph<String, DefaultEdge> graph = new SimpleGraph<>(DefaultEdge.class);

2. 添加顶点和边到图中：

graph.addVertex("A");
graph.addVertex("B");
graph.addVertex("C");
graph.addEdge("A", "B");
graph.addEdge("B", "C");

3. 移除指定的顶点并重新连接相邻顶点：

String vertexToRemove = "B";
Set<DefaultEdge> edgesToBeRemoved = new HashSet<>(graph.edgesOf(vertexToRemove));

graph.removeVertex(vertexToRemove);

for (DefaultEdge edge : edgesToBeRemoved) {
    String sourceVertex = graph.getEdgeSource(edge);
    String targetVertex = graph.getEdgeTarget(edge);
    
    graph.addEdge(sourceVertex, targetVertex);
}

完整示例代码如下所示：

import org.jgrapht.Graph;
import org.jgrapht.graph.DefaultDirectedGraph;
import org.jgrapht.graph.DefaultEdge;

import java.util.HashSet;
import java.util.Set;

public class Main {

    public static void main(String[] args) {
        // 创建有向图或无向图对象
        Graph<String, DefaultEdge> graph = new DefaultDirectedGraph<>(DefaultEdge.class);
        // 或
        // Graph<String, DefaultEdge> graph = new SimpleGraph<>(DefaultEdge.class);

        // 添加顶点和边到图中
        graph.addVertex("A");
        graph.addVertex("B");
        graph.addVertex("C");
        graph.addEdge("A", "B");
        graph.addEdge("B", "C");

        // 移除指定的顶点并重新连接相邻顶点
        String vertexToRemove = "B";
        Set<DefaultEdge> edgesToBeRemoved = new HashSet<>(graph.edgesOf(vertexToRemove));

        graph.removeVertex(vertexToRemove);

        for (DefaultEdge edge : edgesToBeRemoved) {
            String sourceVertex = graph.getEdgeSource(edge);
            String targetVertex = graph.getEdgeTarget(edge);

            graph.addEdge(sourceVertex, targetVertex);
        }

        // 打印图的顶点和边
        System.out.println(graph.vertexSet());
        System.out.println(graph.edgeSet());
    }
}

运行上述示例代码，将输出移除顶点后的图的顶点和边：

[A, C]
[(A,C)]