LEETCODE，[Lintcode]102. Linked List Cycle/[Leetcode]

106. Convert Sorted List to Binary Search Tree/109. Convert Sorted List to Binary Search Tree

• 本題難度: Medium/Easy
• Topic: Linked List

Description

A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.

Return a deep copy of the list.

Challenge
Could you solve it with O(1) space?
```

我的代碼

"""
Definition of ListNode
class ListNode(object):def __init__(self, val, next=None):self.val = valself.next = next
"""class Solution:"""@param head: The first node of linked list.@return: True if it has a cycle, or false"""def hasCycle(self, head):# write your code heretry:slow = headfast = head.nextwhile(slow is not fast):slow = slow.nextfast = fast.next.nextreturn Trueexcept:return False

思路

快慢指針
用try..except