【Leetcode】141 Linked List Cycle

【题目】{ 链接 }

/**
 * 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) 
    {
    	ListNode * fast, *slow;
    	fast = slow = head;
    	while(fast && fast->next)
    	{
    		slow = slow->next;
    		fast = fast->next->next;
    		if(fast == slow)
    			return true;
    	}
        return false;
    }
};