题解 | #删除链表中重复的结点#

#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pHead ListNode类 
# @return ListNode类
#
class Solution:
    def deleteDuplication(self , pHead: ListNode) -> ListNode:
        # write code here
        pre = ListNode(-1)
        ppre = pre
        pre.next = pHead
        while pHead and pHead.next:
            if pHead.val != pHead.next.val: 
                pre.next = pHead
                pre = pre.next
                pHead = pHead.next
            else:
                temp = pHead.val
                while pHead and pHead.val == temp:
                    pHead = pHead.next
                pre.next = pHead
        return ppre.next
                

注意这里的关键是：在用while循环删除重复节点时，当退出循环时要让pre的下一个节点指向当前工作节点；大循环不遍历最后一个节点，小循环要遍历。