剑指offer--面试题57：删除链表中重复的结点

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

python实现：

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    def deleteDuplication(self, pHead):
        # write code here
        if pHead is None:
            return None
        #先看头结点是否有重复
        p = pHead
        isDuplicated = False
        while p and p.next:
            if p.val==p.next.val:
                isDuplicated = True
                p = p.next
            else:
                if isDuplicated:
                    pHead = p.next
                    p = pHead
                    isDuplicated=False
                else:
                    break
         
        if isDuplicated:
             pHead = p.next  
                 
        if pHead is None:
            return None
         
        p = pHead.next
        pre = pHead
        isDuplicated = False
        while p and p.next:
            if p.val == p.next.val:
                isDuplicated = True
                p = p.next
            else:              
                if isDuplicated:
                    pre.next = p.next
                    isDuplicated = False
                else:
                    pre.next = p
                    pre = p
                p = p.next
        if isDuplicated:
            pre.next = p.next
        return pHead