力扣：876. 链表的中间结点

876. 链表的中间结点

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
 //快慢指针算法
 //快指针走两步，慢指针走一步
struct ListNode* middleNode(struct ListNode* head)
{
    struct ListNode* fast=head;
    struct ListNode* slow=head;
    while(fast&&fast->next!=NULL)
    {
        fast=fast->next->next;
        slow=slow->next;
    }
    return slow;
}