linkedlist.java

Create and Reverse a linkedlist 

// { Driver Code Starts
import java.util.*;
import java.io.*;

class Node{
    int data;
    Node next;
    
    Node(int x){
        data = x;
        next = null;
    }
    
}
class Linkedlist{
	static void printList(Node node) 
	{ 
		while (node != null) 
		{ 
			System.out.print(node.data + " "); 
			node = node.next; 
		} 
		System.out.println(); 
	}
    public static void main(String args[]) throws IOException { 
        
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        
        while(t > 0){
        
        	int n = sc.nextInt();
        
            Node head = new Node(sc.nextInt());
            Node tail = head;
        
            for(int i=0; i<n-1; i++)
            {
                tail.next = new Node(sc.nextInt());
                tail = tail.next;
            }
        
            Solution ob = new Solution();
            head = ob.reverseList(head);
            printList(head); 
            t--;
        }
    } 
} 
   // } Driver Code Ends
class Solution
{
    //Function to reverse a linked list.
    Node reverseList(Node head)
    {
       Node nextnode=null;
       Node prev=null;
       Node curr=head;
       while(curr!=null){
           nextnode=curr.next;
           curr.next=prev;
           prev=curr;
           curr=nextnode;
       }
       head=prev;
       return head;
       
    }
}