leetcode——19. 删除链表的倒数第N个节点

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

class Solution:
    def removeNthFromEnd(self, head: ListNode, n: int) -> ListNode:
        if head.next==None and n==1:
            return 
        a=[]
        while head:
            a.append(head.val)
            head=head.next
        #print(a)
        #print(len(a))
        a.pop(len(a)-n)
        head=ListNode(a[0])
        p=head
        for i in range(1,len(a)):
            p.next=ListNode(a[i])
            p=p.next
        return head