4th question, Java

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//'main' method must be in a class 'Rextester'.
//openjdk version '11.0.5'

import java.util.*;
import java.lang.*;

class Rextester
{  
    static int dfs(int info, boolean visited[], LinkedList<Integer> a)
    {
        visited[info]= true;
      //  Iterator<Integer> x=a[info].Iterator();
     //   ListIterator list_Iter = list.listIterator(2);
        ListIterator<Integer> x=a.listIterator(info);
        while(x.hasNext())
        {
           int y;
           y=x.next();
           if(visited[y] == false)
               return 1 + dfs(y,visited,a);
        }
    }
    public static void main(String args[])
    {
        Scanner sc=new Scanner(System.in);
        String str=sc.nextLine();
        int inode=sc.nextInt();
        int i,j=0;
        int n=0,v=0;
        
        String words[]=str.split(" ");
        for(String s:words)
            n++;
        String N="N";
        int b[]=new int[n];
        int tmp;
        //System.out.println(n);
        for(String s:words)
        {
            //System.out.println(s);
            if(s.equals(N))
                b[j++]=0;
            else
            {
                tmp=Integer.parseInt(String.valueOf(s));;
                b[j++]=tmp; 
                v++;
            }
        }
        boolean visited[]=new boolean[v];
     //   for(i=0;i<n;i++)
       //     System.out.print(b[i]+" ");
        
           LinkedList<Integer> a[]=new LinkedList[n];
      
        for(i=0;i<n;i++)
            a[i]=new LinkedList<>();
       
       i=0;
        for(j=1;j<n;)
        {
            
           while(i<n && b[i]==0)
               i++;
            
            if(i>=n)
                break;
          //  System.out.println(b[i]);
            if(b[j]!=0)
            {
                a[b[i]].addFirst(b[j]);
                a[b[j]].addFirst(b[i]);
             
            }
            j++;
            if(j >= n) break;
            if(b[j]!=0)
            {
                 a[b[i]].addFirst(b[j]);
                 a[b[j]].addFirst(b[i]);
                
            }
            i++; j++;
        }
      //  System.out.println("55555555");
        for ( i = 1; i <n ; i++)
        {
            if(a[i].size()>0) {
                System.out.print("Vertex " + i + " is connected to: ");
                for (j = 0; j < a[i].size(); j++) {
                    System.out.print(a[i].get(j) + " ");
                }
                System.out.println();
            }
        }   
        
       int ans= dfs(inode,visited,a);
        
        System.out.println(ans);
        
        
    }
}

[ - ] Show input
Compilation time: 0.83 sec, absolute service time: 1,02 sec