题解 | #判断链表中是否有环#

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 {
	// write code here
	pre, cur := head, head
	for pre != nil && cur != nil && cur.Next != nil {
		pre = pre.Next      //走1步
		cur = cur.Next.Next //走2步
		if pre == cur {
			return true
		}
	}
	return false
}