83. 删除排序链表中的重复元素

83. 删除排序链表中的重复元素
# 由于是已排序的链表，判断前后是否为相同元素如果是则连接下下个不是则向前移动
#code：
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def deleteDuplicates(self, head: Optional[ListNode]) -> Optional[ListNode]:
        if not head:
            return head
        cur = head
        while cur.next:
            if cur.val==cur.next.val:
                cur.next=cur.next.next
            else:
                cur = cur.next
        return head
#虽然本题很简单，但可以用多种方法去试试
#现在使用递归的方法
class Solution(object):
    def deleteDuplicates(self, head):
        if not head or not head.next:
            return head
        if head.val!=head.next.val:
            head.next =self.deleteDuplicates(head.next)
        else:
            move = head.next
            while move.next and head.val==move.next.val:
                move = move.next
            return self.deleteDuplicates(move)
        return head