[LintCode] Linked List Cycle 单链表中的环

Given a linked list, determine if it has a cycle in it.

Example
Given -21->10->4->5, tail connects to node index 1, return true

Challenge
Follow up:
Can you solve it without using extra space?

LeetCode上的原题，请参见我之前的博客Linked List Cycle。

class Solution {

public:

    /**

     * @param head: The first node of linked list.

     * @return: True if it has a cycle, or false

     */

    bool hasCycle(ListNode *head) {

        if (!head) return false;

        ListNode *slow = head, *fast = head;

        while (fast && fast->next) {

            slow = slow->next;

            fast = fast->next->next;

            if (slow == fast) return true;

        }

        return false;

    }

};

巴特西

[LintCode] Linked List Cycle 单链表中的环

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