Question

我正在尝试修改Jgrapht的函数，将参数作为点的几个坐标（int，int）。我创建了一个由（x，y）定义的类和Point对象，并将其作为directedGraph的参数

    public class Point {

      public int x;
      public int y;

      public Point(int x, int y) 
      {
        this.x = x;
        this.y = y;
      }
      @Override
        public String toString() {
        return ("[x="+x+" y="+y+"]");
      }
    }
  // --------------------------------------------------------------

    public class DirectedGraphDemo {
      public  void graph(String args[]) {

        //Create the directed graph
        public DirectedGraph<Point, DefaultEdge> directedGraph = new DefaultDirectedGraph<Point, DefaultEdge>(DefaultEdge.class);

        // constructs a directed graph with the specified vertices and edges

        directedGraph.addVertex(1,2);
        directedGraph.addVertex(1,3);
        directedGraph.addVertex(1,4);

        directedGraph.addEdge((1,2),(1,3));
        directedGraph.addEdge((1,3),(1,4));
        directedGraph.addEdge((1,4),(1,2));

        // computes all the strongly connected components of the directed graph
        StrongConnectivityInspector sci =
          new StrongConnectivityInspector(directedGraph);
        List stronglyConnectedSubgraphs = sci.stronglyConnectedSubgraphs();

        // prints the strongly connected components
        System.out.println("Strongly connected components:");
        for (int i = 0; i < stronglyConnectedSubgraphs.size (); i++) {
          System.out.println(stronglyConnectedSubgraphs.get(i));
        }
        System.out.println();

        // Prints the shortest path from vertex i to vertex c. This certainly
        // exists for our particular directed graph.
        System.out.println("Shortest path from (1,2) to (1,3):");
        List path =
          DijkstraShortestPath.findPathBetween(directedGraph, (1,2),(1,3);
        System.out.println(path + "\n");

        // Prints the shortest path from vertex c to vertex i. This path does
        // NOT exist for our particular directed graph. Hence the path is
        // empty and the variable "path"; must be null.
        System.out.println("Shortest path from (1,2) to (1,3):");
        path = DijkstraShortestPath.findPathBetween(directedGraph, (1,2), (1,3));
        System.out.println(path);
      }
    }

我要做的是能够使用：

directedGraph.addVertex(x1,y1);
directedGraph.addVertex(x2,y2);
directedGraph.addEdge((x1,y1), (x2,y2));
path = DijkstraShortestPath.findPathBetween(directedGraph,(x1,y1),(x2,y2));

当我运行代码时，我得到错误“方法addVertex不适用于参数（int，int）”，即使参数是Point，由（int，int）定义。我该如何开展这项工作？

我使用基于Java的处理

Answer 1

通过查看the API可以最好地回答这些问题。

addVertex()函数采用Point参数，如您在通用参数中指定的那样。您不能只用两个int值替换它们并期望它能够正常工作。相反，您必须提供Point值：

directedGraph.addVertex(new Point(1,2));

同样，您还必须将Point值传递给DijkstraShortestPath.findPathBetween()函数：

path = DijkstraShortestPath.findPathBetween(directedGraph, new Point(x1,y1),new Point(x2,y2));

将方法参数更改为对象时出错（jgrapht库）

1 个答案: