打卡群刷题总结0625——删除链表的倒数第N个节点

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

class Solution(object):
    def removeNthFromEnd(self, head, n):
        """
        :type head: ListNode
        :type n: int
        :rtype: ListNode
        """
        fast = head
        while n > 0:
            fast = fast.next
            n -= 1

        # 头结点
        node = ListNode(0)
        node.next = head
        head = node

        slow = head
        while fast:
            fast = fast.next
            slow = slow.next

        node = slow.next
        slow.next = slow.next.next
        del node
        return head.next