//iterative
public ListNode ReverseList(ListNode head)
{
ListNode prev = null;
var current= head;
while(current!=null)
{
var next = current.next;
current.next=prev;
prev =current;
current=next;
}
return prev;
}
// recursive
public ListNode ReverseList(ListNode head)
{
if(head==null || head.next == null)
return head;
var t2 = ReverseList(head.next);
head.next.next = head;
head.next = null;
return t2;
}
// Java program for reversing the linked list
class LinkedList {
static Node head;
static class Node {
int data;
Node next;
Node(int d)
{
data = d;
next = null;
}
}
/* Function to reverse the linked list */
Node reverse(Node node)
{
Node prev = null;
Node current = node;
Node next = null;
while (current != null) {
next = current.next;
current.next = prev;
prev = current;
current = next;
}
node = prev;
return node;
}
// prints content of double linked list
void printList(Node node)
{
while (node != null) {
System.out.print(node.data + " ");
node = node.next;
}
}
// Driver Code
public static void main(String[] args)
{
LinkedList list = new LinkedList();
list.head = new Node(85);
list.head.next = new Node(15);
list.head.next.next = new Node(4);
list.head.next.next.next = new Node(20);
System.out.println("Given Linked list");
list.printList(head);
head = list.reverse(head);
System.out.println("");
System.out.println("Reversed linked list ");
list.printList(head);
}
}
// This code has been contributed by Mayank Jaiswal
LinkedList<Integer> ll = new LinkedList<>();
ll.add(1);
ll.add(2);
ll.add(3);
System.out.println(ll);
LinkedList<Integer> ll1 = new LinkedList<>();
ll.descendingIterator().forEachRemaining(ll1::add);
System.out.println(ll1);