在广度优先搜索中找到孩子的父母

我试图在广度优先搜索中找到孩子的父母，考虑到邻居很容易找到的未加权的无向图，但是我不知道如何与孩子一起打印父母 . 这是代码

/*
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package bfs;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;

public class BreadthFirstSearchExample
{ 

 private Queue<Node> queue;
 static ArrayList<Node> nodes=new ArrayList<Node>();
 static class Node
 {
  int data;
  boolean visited;

  Node(int data)
  {
   this.data=data;

  }
 }

 public BreadthFirstSearchExample()
 {
  queue = new LinkedList<Node>();
 }

 // find neighbors of node using adjacency matrix
 // if adjacency_matrix[i][j]==1, then nodes at index i and index j are connected
 public ArrayList<Node> findNeighbours(int adjacency_matrix[][],Node x)
 {
  int nodeIndex=-1;

  ArrayList<Node> neighbours=new ArrayList<Node>();
  for (int i = 0; i < nodes.size(); i++) {
   if(nodes.get(i).equals(x))
   {
    nodeIndex=i;
    break;
   }
  }

  if(nodeIndex!=-1)
  {
   for (int j = 0; j < adjacency_matrix[nodeIndex].length; j++) {
    if(adjacency_matrix[nodeIndex][j]==1)
    {
     neighbours.add(nodes.get(j));
    }
   }
  }
  return neighbours;
 }

 public  void bfs(int adjacency_matrix[][], Node node)
 {
  queue.add(node);
  node.visited=true;
  int nf =0;
  while (!queue.isEmpty())
  {
   nf = queue.size();
   Node element=queue.remove();
   System.out.print(element.data + "\t");


   ArrayList<Node> neighbours=findNeighbours(adjacency_matrix,element);
   for (int i = 0; i < neighbours.size(); i++) {
    Node n=neighbours.get(i);
    int mf = neighbours.size();

    if(n!=null && !n.visited)
    {
     queue.add(n);
     n.visited=true;
     //System.out.print("neighbours"+ n.data + "\t");
//     System.out.print("vertices" + nf + "\t");
//     System.out.print("degree" + mf + "\t");

    }
   }

  }
 }

 public static void main(String arg[])
 {

   Node node40 =new Node(40);
   Node node10 =new Node(10);
   Node node20 =new Node(20);
   Node node30 =new Node(30);
   Node node60 =new Node(60);
   Node node50 =new Node(50);
   Node node70 =new Node(70);

   nodes.add(node40);
   nodes.add(node10);
   nodes.add(node20);
   nodes.add(node30);
   nodes.add(node60);
   nodes.add(node50);
   nodes.add(node70);
   int adjacency_matrix[][] = {
     {0,1,1,0,0,0,0},  // Node 1: 40
     {1,0,0,1,0,0,0},  // Node 2 :10
     {1,0,0,1,1,1,0},  // Node 3: 20
     {0,1,1,0,1,0,0},  // Node 4: 30
     {0,0,1,1,0,0,1},  // Node 5: 60
     {0,0,1,0,0,0,1},  // Node 6: 50
     {0,0,0,0,1,1,0},  // Node 7: 70
   };
   System.out.println("The BFS traversal of the graph is ");
   BreadthFirstSearchExample bfsExample = new BreadthFirstSearchExample();
   bfsExample.bfs(adjacency_matrix, node40);

 }
}

输出是 40 10 20 30 60 50 70

我希望程序将输出显示为

40 10 parent:40 20 parent:40 30 parent:10 60 parent:20 50 parent:20 70  parent:60