Leetcode 206 Reverse Linked List

Reverse a singly linked list.
Solution 1: easy

 public class Solution {  
   public ListNode reverseList(ListNode head) {  
     ListNode i=head, j=null;  
     while (i!=null) {  
       ListNode next=i.next;  
       i.next=j;  
       j=i;  
       i=next;  
     }  
     return j;  
   }  
 }