链表:
题目描述:
判断给定的链表中是否有环
扩展:
你能给出不利用额外空间的解法么?
Given a linked list, determine if it has a cycle in it.
Follow up:
Can you solve it without using extra space?
输入描述:
输出描述:
示例1:
输入:
输出:
代码:
public class Solution {
public boolean hasCycle(ListNode head) {
if(head==null)
return false;
ListNode fast=head;
ListNode slow=head;
while(fast!=null&&fast.next!=null){
fast=fast.next.next;
slow=slow.next;
if(fast==slow)
return true;
}
return false;
}
}