一个单链表,从任一给定的位置(pr, p)开始，将指针p右移k个结点。如果p移出链表，则将p置为0，并让pr停留在链表最右边的结点上 从任一给定的位置(pr, p)开始，将指针p左移k个结点。如果p移出链表，则将p置为0，并让pr停留在链表最左边的结点上。-A single list from any given location (pr, p) to start, move the pointer to the right p k nodes. Removed from the list if p, then p is set to 0, and so remain in the list pr rightmost node　from any given position (pr, p) starts, the pointer p k nodes left. Removed from the list if p, then p is set to 0, and so remain in the pr leftmost node list.