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 head is None:
            return head
        pre = head
        cur = pre.next
        while True:
            if cur is None:
                break
            if cur.val != pre.val:
                pre.next = cur
                pre = cur
                cur =pre.next
                continue
            else:
                cur =cur.next

        pre.next = cur
        return head