剑指 Offer 22. 链表中倒数第k个节点

剑指 Offer 22. 链表中倒数第k个节点

思路：

先计算链表的长度，然后遍历到n - k

代码：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* getKthFromEnd(ListNode* head, int k) {
        int n = 0;
        for(auto p = head;p;p = p->next) n++;
        auto dummy = head;
        for(int i = 0; i < n - k; i++) dummy = dummy->next;
        return dummy;
    }
};