1 /**
2 * Definition for singly-linked list.
3 * struct ListNode {
4 * int val;
5 * ListNode *next;
6 * ListNode(int x) : val(x), next(NULL) {}
7 * };
8 */
9 class Solution {
10 public:
11 bool hasCycle(ListNode *head) {
12 // IMPORTANT: Please reset any member data you declared, as
13 // the same Solution instance will be reused for each test case.
14 ListNode * itr = head;
15 int n = 1;
16 while (true){
17 if (itr==NULL)
18 return false;
19 ListNode * tmp = itr;
20 for (int i=0; i<n; i++){
21 tmp = tmp->next;
22 if (tmp==NULL)
23 return false;
24 else if (tmp == itr)
25 return true;
26 }
27 n++;
28 itr = itr->next;
29 }
30 return false;
31 }
32 };
