题目描述：
中文：
给定一个排序链表，删除所有含有重复数字的节点，只保留原始链表中 没有重复出现 的数字。
示例 1:
输入: 1->2->3->3->4->4->5
输出: 1->2->5
示例 2:
输入: 1->1->1->2->3
输出: 2->3
英文：
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
Example 1:
Input: 1->2->3->3->4->4->5
Output: 1->2->5
Example 2:
Input: 1->1->1->2->3
Output: 2->3
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None class Solution(object):
def deleteDuplicates(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if head ==None or head.next == None:
return head
dummy = ListNode(0)
dummy.next = head
p = dummy
tmp = dummy.next
while p.next:
while tmp.next and tmp.next.val == p.next.val:
tmp = tmp.next
if tmp == p.next:
p = p.next
tmp = p.next
else:
p.next = tmp.next
return dummy.next
题目来源：力扣