力扣 ——Remove Duplicates from Sorted List II（删除排序链表中的重复元素 II）python实现

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