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
    if(head==nil){
        return false
    }
    fast := head;
    slow := head;
    for fast!=nil && slow!=nil {
        slow = slow.Next;
        if(fast.Next!=nil){
            fast=fast.Next.Next;
        }else{
            return false;
            }
        if(fast==slow){
            return true;
        }
    }
    return false;    
}