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
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;
}
};