C++ 代码

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* findKthToTail(ListNode* pListHead, int k) {
        if(!pListHead || !pListHead->next) return nullptr;
        auto cur = pListHead;
        while(cur && k --){
            cur = cur->next;
        }
        if(!cur && k) return nullptr;
        auto ret = pListHead;
        while(cur){
            cur = cur->next;
            ret = ret->next;
        }
        return ret;
    }
};