题解 | #删除链表的倒数第n个节点#

# 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 
# @param n int整型 
# @return ListNode类
#
class Solution:
    def removeNthFromEnd(self , head: ListNode, n: int) -> ListNode:
        # write code here
        res = ListNode(0)
        pre=res
        d=head
        pre.next=head
        cur = head
        temp=cur.next
        j=0
        while True:
            if d:
                j=j+1
                d=d.next
            else:
                break
        while j >= n:
            for i in range(j-n):
                if cur:
                    pre=cur
                    cur=cur.next
                    temp=cur.next
            if temp:
                 pre.next=temp
            else:
                 pre.next=None
            return res.next
        return None