链接：19. 删除链表的倒数第 N 个结点 - 力扣（LeetCode）

直接写

 1 # Definition for singly-linked list.
 2 # class ListNode(object):
 3 #     def __init__(self, val=0, next=None):
 4 #         self.val = val
 5 #         self.next = next
 6 class Solution(object):
 7     def removeNthFromEnd(self, head, n):
 8         """
 9         :type head: Optional[ListNode]
10         :type n: int
11         :rtype: Optional[ListNode]
12         """
13         length = 0
14         currNode = head
15         while currNode:
16             length += 1
17             currNode = currNode.next
18         if length == n:
19             return head.next
20         n = length - n
21         currNode = head
22         if n == 0:
23             return None
24         while n > 1:
25             currNode = currNode.next
26             n -= 1
27         currNode.next = currNode.next.next
28         return head
29             
30