package main import . "nc_tools" /* * type ListNode struct{ * Val int * Next *ListNode * } */ /** * * @param head ListNode类 * @return bool布尔型 */ func hasCycle( head *ListNode ) bool { fast,slow := head,head for fast != nil && slow != nil { slow = slow.Next if fast.Next == nil { return false } fast = fast.Next.Next if slow == fast && slow != nil { return true } } return false }