Leetcode 142. Linked List Cycle II
# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution(object): def detectCycle(self, head): """ :type head: ListNode :rtype: ListNode """ try: slow = head fast = head.next while slow is not fast: slow = slow.next fast = fast.next.next slow=head.next while slow is not fast: slow=slow.next fast=fast.next return slow except: return