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
 */
bool hasCycle(struct ListNode* head ) {
    // write code here
    struct ListNode* fast,* slow;
    if(head==NULL)
    {
        return false;
    }
    fast = slow = head;
    while(fast&&fast->next)
    {
        
        
        
        fast = fast->next->next;
       
        slow = slow->next;
        if(fast==slow)
        {
            return true;
        }
    }
    return false;
}