题解 | #牛群排列去重#

# class ListNode:
#     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 head ListNode类 
# @return ListNode类
#
class Solution:
    def deleteDuplicates(self , head: ListNode) -> ListNode:
        # write code here
        if not head:
            return head
        pre=head
        cur=head
        cur=cur.next
        cow=[]
        cow.append(pre.val)
        while cur:
            if  cur.val not in cow:
                pre=cur
                cow.append(cur.val)
            else:
                pre.next=cur.next
            cur=cur.next
        return head