[LeetCode]82 删除排序链表中的重复元素II

题目描述

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

代码

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# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def deleteDuplicates(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        st, h, dup, fin = [], head, 0, 0
        while h or (fin and dup):
            if not fin and st and st[-1].val == h.val:
                dup = 1
            else:
                if dup:
                    dup = 0
                    st.pop()
                    if st:
                        st[-1].next = h
                    else:
                        head = h
                    if fin:
                        return head
                st.append(h)
                while len(st) > 2:
                    del st[0]
            h = h.next
            fin = not h
        return head