Reverse a Singly LinkedList

Reverse a Singly LinkedList

 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */

public Class Solution{

    public static ListNode reverseList(ListNode head){
        if(head == null || head.next == null){
            return head;
        }
        
        ListNode next = head.next;
        head.next = null;
        while(next != null){
            ListNode temp = next.next;
            next.next = head;
            head = next;
            next = temp;
        }
        
        return head;
    }
}