LeetCoder - Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

/**

 * Definition for singly-linked list.

 * public class ListNode {

 *     int val;

 *     ListNode next;

 *     ListNode(int x) {

 *         val = x;

 *         next = null;

 *     }

 * }

 */

public class Solution {

    public ListNode deleteDuplicates(ListNode head) {

        if(head==null) {

            return null;

        }

        ListNode cur = head;

        ListNode next = head.next;

        while(cur!=null) {

            while(next!=null && cur.val==next.val) {

                next = next.next;

            }

            cur.next = next;

            cur = next;

        }

        return head;

    }

}