/**

  • Definition for singly-linked list.
  • struct ListNode {
  • int val;

  • ListNode *next;

  • ListNode(int x) : val(x), next(NULL) {}
  • }; */ class Solution { public: bool hasCycle(ListNode *head) { if(head==NULL) return false; ListNode *node=head; int up=10; for(int j=0;j<16;++j){ for(int i=0;i<up;++i){ if(node->next!=NULL){ node=node->next; } else return false; } //check out ListNode test=node; for(int i=0;i<up;++i){ if(node->next!=NULL){ node=node->next; if(node==test) return true; } else return false; } up=2; } return false; } };