[LeetCode]Linked List Cycle

最新推荐文章于 2021-11-01 14:38:45 发布

原创最新推荐文章于 2021-11-01 14:38:45 发布 · 1k 阅读

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本文介绍了使用快慢指针法实现链表中是否存在循环的算法，并提供了代码实现细节。

/**
 * 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) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        ListNode* fastWalker = head;
        ListNode* slowWalker = head;
        
        while(fastWalker && slowWalker)
        {
            fastWalker = fastWalker->next;
            if(fastWalker) fastWalker = fastWalker->next;
            else break;
            slowWalker = slowWalker->next;
            
            if(fastWalker == slowWalker) return true;
        }
        
        return false;
    }
};