LeetCode-Remove Duplicates from Sorted List

题目：https://oj.leetcode.com/problems/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.

源码：Java版本
算法分析：时间复杂度O(n)，空间复杂度O(1)

/**
 * 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 node=head.next;
        ListNode newNode=head;
        while(node!=null) {
            if(node.val!=newNode.val) {
                newNode.next=node;
                newNode=node;
            }
            node=node.next;    
        }
        newNode.next=null;
        return head;
    }
}