原题
找链表的中点。
样例
链表 1->2->3的中点是2。链表 1->2的中点是1。
解题思路
- 快慢指针一起跑，快的到终点，慢的到中点
完整代码
"""
Definition of ListNode
class ListNode(object):
def __init__(self, val, next=None):
self.val = val
self.next = next
"""
class Solution:
# @param head: the head of linked list.
# @return: a middle node of the linked list
def middleNode(self, head):
# Write your code here
if head is None or head.next is None:
return head
slow, fast = head, head.next
while fast is not None and fast.next is not None:
slow = slow.next
fast = fast.next.next
return slow
