快慢指针有环的话,快慢指针在某一时刻一定会相等 class ListNode: def __init__(self, x): self.val = x self.next = None # # # @param head ListNode类 # @return bool布尔型 # class Solution: def hasCycle(self , head): # 0 or 1 if not head or not head.next: return False slow, fast = head, head.next while slow != fast: slow = slow.nex...