class Solution { public: bool hasCycle(ListNode *head) { if(!head) return false; ListNode* p = head; ListNode* q = head; while(p){ p = p->next; q = q->next; if(p){ p = p->next; if(p==q) return true; } } return false; } };
class Solution { public: bool hasCycle(ListNode *head) { if(!head) return false; ListNode* p = head; ListNode* q = head; while(p){ p = p->next; q = q->next; if(p){ p = p->next; if(p==q) return true; } } return false; } };