【LeetCode】Linked List Cycle

Linked List Cycle

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

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

做完Linked List Cycle II在做这题简直就是阉割版。。

fast每次前进两步，slow每次前进一步，如果相遇则为true，否则false


class Solution

{

public:

    bool hasCycle(ListNode *head)

    {

        if(head == NULL)

            return false;

        ListNode* fast = head;

        ListNode* slow = head;

        do

        {

            if(fast->next && slow->next)

            {

                fast = fast->next;

                slow = slow->next;

            }

            else

                return false;


if(fast->next)

                fast = fast->next;

            else

                return false;

        }while(fast != slow);


return true;

    }

};

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时间： 2024-12-09 23:19:49

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