LinkedList for each index in the LinkedList Array

Question

What is the problem here?.I'm trying to implement the graph data structure,using the adjacency lists,by utilising the Collections from the util package.Here

LinkedList array which holds some integer. Each element of that LinkedList holds another LinkedList of type: node.

But during the compilation process, it says incompatible types. How to resolve this problem?

 //Sum of dependencies in a graph
import java.util.*;
class node
{
     int vertex,weight;
     public node(int v,int w)
     {
          vertex = v;
          weight = w;
     }
}
public class dependency
{
 int V;
 LinkedList<Integer> adj[];
 public dependency(int v)
 {
      V = v;
      adj = new LinkedList<Integer>[v];
      for (int i=0;i < v ;i++ ) {
           adj[i] = new LinkedList<node>();
      }
 }
 void addEdge(int v,node l)
 {
      adj[v].add(l);
 }
 void BFS(int s)
 {
      boolean visited[] = new boolean[V];
      LinkedList<Integer> queue = new LinkedList<Integer>();
      visited[s] = true;
      queue.add(s);
      while(queue.size() != 0)
      {
           s = queue.poll();
           System.out.println(s+" ");

           Iterator<Integer> i = adj[s].listIterator();
           while(i.hasNext())
           {
                int n = i.next();
                if(!visited[n])
                {
                     visited[n] = true;
                     queue.add(n);
                }
           }
      }
 }
 public static void main(String[] args) {
      graph g = new graph(4);
      node a = new node(1,10);
      node b = new node(2,20);
      node c = new node(2,30);
      node d = new node(0,20);
      node e = new node(3,30);
      node f = new node(3,20);
      g.addEdge(0, a);
      g.addEdge(0, b);
      g.addEdge(1, c);
      g.addEdge(2, d);
      g.addEdge(2, e);
      g.addEdge(3, f);

    System.out.println("Following is Breadth First Traversal "+
                       "(starting from vertex 2)");

    g.BFS(2);
 }
}

Neel Neel · Accepted Answer · 2018-04-10T19:13:52

You've declared an array of LinkedLists of type LinkedList<Integer>, but you're trying to store LinkedList<node> in the array. It doesn't appear that you're ever using the weight attribute of node, so you should change adj[i] = new LinkedList<node>(); to adj[i] = new LinkedList<Integer>();.

LinkedList for each index in the LinkedList Array

1 Answers