leetcode | 面试题 02.02 | 返回倒数第 k 个节点

用的是快慢指针的思想

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    int kthToLast(ListNode* head, int k) {        
        ListNode* fast = head;
        ListNode* slow = head;

        while(fast != nullptr)
        {
            fast = fast->next;
            if(k == 0)
            {
                slow = slow->next;
            }
            else
            {
                k--;
            }
        }
        return slow->val;
    }
};