删除链表中重复的结点.py

'''
删除链表中重复的结点
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 = None
class Solution:
    def deleteDuplication(self, pHead):
        if pHead == None:
            return
        preHead = None
        pNode = pHead
        while pNode != None:
            needDelete = False
            nextNode = pNode.next
            if nextNode != None and nextNode.val == pNode.val:
                needDelete = True
            if needDelete == False:
                preHead = pNode
                pNode = pNode.next
            else:
                nodeVal = pNode.val
                pToBeDel = pNode
                while pToBeDel != None and pToBeDel.val == nodeVal:
                    pToBeDel = pToBeDel.next
                if preHead == None:
                    pHead = pToBeDel
                    pNode = pToBeDel
                    continue
                else:
                    preHead.next = pToBeDel
                pNode = preHead
        return pHead

node1 = ListNode(1)
node2 = ListNode(2)
node3 = ListNode(3)
node4 = ListNode(3)
node5 = ListNode(4)
node6 = ListNode(4)
node7 = ListNode(5)
node1.next = node2
node2.next = node3
node3.next = node4
node4.next = node5
node5.next = node6
node6.next = node7

s = Solution()
print(s.deleteDuplication(node1).next.next.val)