题解 | #判断链表中是否有环#

#include <stdbool.h>
#include <stdlib.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* low=head;
    struct ListNode* fast=head->next;
    if(low==NULL||fast==NULL)return false;
    while(fast!=NULL){
        if(fast==low)return true;
        else{
            low=low->next;
            fast=fast->next;
            if(fast==NULL)return false;
            fast=fast->next;
        }
    }
    return false;
    
}

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