Python ：删除链表中重复的节点

牛客网上的剑指 offer的在线编程：

题目描述:

在一个排序的链表中，存在重复的结点，请删除该链表中重复的结点，重复的结点不保留，返回链表头指针。 例如，链表1->2->3->3->4->4->5 处理后为 1->2->5

# -*- coding:utf-8 -*-class ListNode:    def __init__(self, x):        self.val = x        self.next = Noneclass Solution:    def deleteDuplication(self, pHead):        # write code here        if pHead is None or pHead.next is None:            return pHead        bhead = ListNode(pHead.val - 1)        bhead.next = pHead        first_node = bhead        second_node = pHead        while second_node and second_node.next:            if second_node.val == second_node.next.val:                del_val = second_node.val                while second_node and (second_node.val == del_val):                    second_node = second_node.next                first_node.next = second_node            else:                first_node = first_node.next                second_node = second_node.next        return bhead.next