题解 | #判断链表中是否有环#

#include <stdbool.h>
/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

/**
 * 
 * @param head ListNode类 
 * @return bool布尔型
 */
 typedef struct ListNode listnode;
bool hasCycle(struct ListNode* head ) {
    // write code her
    listnode*quick,*slow;
    quick = slow = head;
    while(quick && slow)
    {
        if(quick->next!=NULL)
        {
            quick = quick->next->next;
        }
        else 
        {
            return false;
        }
        slow = slow->next;//快慢指针+碰撞指针
        if(quick==slow)
        {
            return true;
        }
    }
    return false;
}