Find kth node of a linked list from end

Solution:
When we travel the linked list, we can keep two pointers. The first pointer moves k steps and the second pointer begins to move. The distance of two pointers are always k-1 steps. When the first pointer arrives at the end of the linked list, the second pointer is pointing the kth node from end.

Time: O(n)



The other similar question:

输入一个单向链表。如果该链表的结点数为奇数，输出中间的结点；如果链表结点数为偶数，输出中间两个结点前面的一个。