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
钻空子，取100001作为遍历标记，只要遍历过将其数据域变为100001
但是实际情况中数据基本上不会面面俱到
不过双指针适用性更广
/**
* 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) {
if(head == null){
return false;
}
ListNode temp = head;
while(temp != null){
temp.val = 100001;
if(temp.next == null){
return false;
}
if(temp.next.val == 100001){
return true;
}
temp = temp.next;
}
return false;
}
}
