题解 | #判断链表中是否有环#

package main

import . "nc_tools"

/*
 * type ListNode struct{
 *   Val int
 *   Next *ListNode
 * }
 */

func hasCycle(head *ListNode) bool {
	p := head
	q := head
	for p != nil && q != nil {
		p = p.Next
		q = q.Next
		if q != nil {
			q = q.Next
		}
		if q != nil && p == q {
			return true
		}
	}
	return false
	// write code here
}