LeetCode | 面试题 02.02. 返回倒数第 k 个节点

OJ链接

• 思路：定义两个快慢指针，让快指针先提前走k个节点，然后再让慢结点和快结点一起走，当快指针 == NULL时，慢指针就是倒数第k个节点

代码如下：

int kthToLast(struct ListNode* head, int k){
    struct ListNode* slow,*fast;
    slow = fast = head;
    while(k--)
    {
        if(fast == NULL)
            return NULL;
        fast = fast->next;
    }
    while(fast != NULL)
    {
        slow = slow->next;
        fast = fast->next;
    }
    return slow->val;
}