/**
 * 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) {
        stack<ListNode*> s;
        int length=0;
        for(auto p=pListHead;p;p=p->next)
        {
            s.push(p);
            length++;
        }
        if(k>length)
        {
            return NULL;
        }

        while(k>1)
        {
            s.pop();
            k--;
        }

        auto t=s.top();
        return t;

    }
};