链表问题

http://wenku.baidu.com/link?url=mIGD66zTocZ_mjiE6gZ1whhhGnCT1JqktEJX5XD8PfPd4-AQDpKe7z7rvo8t99V0a-9duvIteZiWs_wQtlkKYFsnI4HpIoGQdLMbzq63zia