快慢指针
不要边界判断,直接异常梭哈
# 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
# @return ListNode类
#
class Solution:
def middleNode(self , head: ListNode) -> ListNode:
if not head.next:return head
fast,slow = head,head
while fast or slow:
try:
fast = fast.next.next
slow = slow.next
except:
return slow