题解 | #判断链表中是否有环#
判断链表中是否有环
http://www.nowcoder.com/practice/650474f313294468a4ded3ce0f7898b9
快慢指针，如果链表有环，他们一定会相遇
/**
* Definition for singly-linked list.
* class ListNode {
* int val;
* ListNode next;
* ListNode(int x) {
* val = x;
* next = null;
* }
* }
*/
public class Solution {
public boolean hasCycle(ListNode head) {
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;
}
}
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