面试题 02.02

Implement an algorithm to find the kth to last element of a singly linked list. Return the value of the element.

Note: This problem is slightly different from the original one in the book.

Example:

Input: 1->2->3->4->5 和 k = 2 Output: 4 Note:

k is always valid.

/**
 * 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 *cur = head;
        while (k-- && cur) {
            cur = cur->next;
        }

        while (cur) {
            head = head->next;
            cur = cur->next;
        }
        return head->val;
    }
};