C 解法, 执行用时: 3ms, 内存消耗: 684KB, 提交时间: 2021-09-11

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

C 解法, 执行用时: 3ms, 内存消耗: 688KB, 提交时间: 2021-07-16

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

/**
 * 
 * @param head ListNode类 
 * @return bool布尔型
 */
#include <stdbool.h>
bool hasCycle(struct ListNode* head ) {
    if(head == NULL){
        return false;
    }
    struct ListNode *pre = head->next;
    struct ListNode *lag = head;
    while(pre){
        if(lag == pre){
            return true;
        }
        lag = lag->next;
        pre = pre->next;            
        if(pre){
            pre = pre->next;
        }        
    }
    return false;
}

C 解法, 执行用时: 3ms, 内存消耗: 696KB, 提交时间: 2021-09-15

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

/**
 * 
 * @param head ListNode类 
 * @return bool布尔型
 */
#include<stdbool.h>
bool hasCycle(struct ListNode* head ) {
    // write code here、
    struct ListNode *slow, *fast;
    slow = fast = head;
    
    
    while(slow && fast){
        slow = slow->next;
        if(fast->next)
            fast = fast->next->next;
        else
            return false;
        if(fast == slow)
            return true;
    }
    return false;
}

C 解法, 执行用时: 3ms, 内存消耗: 696KB, 提交时间: 2021-09-12

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

/**
 * 
 * @param head ListNode类 
 * @return bool布尔型
 */
int hasCycle(struct ListNode* head ) {
    // write code here
    struct ListNode * first;
    struct ListNode * second;
    
    first = head;
    second = head;
    
    while(first != NULL&& first->next != NULL && second !=NULL && second->next !=NULL)
    {
            first = first -> next;            
            second = second ->next ->next;
        if(first == second)
        {
            return 1;
        }      
        
    }
    return 0;
}

C 解法, 执行用时: 3ms, 内存消耗: 768KB, 提交时间: 2021-10-23

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

/**
 * 
 * @param head ListNode类 
 * @return bool布尔型
 */
bool hasCycle(struct ListNode* head ) {
    struct ListNode *a,*b;
    a=b=head;
    if(head==NULL){
        return false;
    }
    while(1){
        a=a->next;
        b=b->next;
        if(b==NULL){
            break;
        }
        b=b->next;
        if(b==NULL){
            break;
        }
        if(a==b){
            return true;
        }
    }
    return false;
}