leetcode83，删除有序链表中的重复元素

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.

难点就一个，就是要考虑到连续3个和3个以上的情况。

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if(head != null)
        {
            ListNode nodeA = head;
            ListNode nodeB = head.next;
            while(nodeB != null)
            {
                if(nodeA.val == nodeB.val){
                    nodeA.next = nodeB.next;
                    nodeB = nodeB.next;
                }else{
                    nodeA = nodeB;
                    nodeB = nodeB.next;
                }
            }
        }
        return head;
    }
}