* REFS:
* http://blog.csdn.net/fightforyourdream/article/details/16353519
* http://blog.csdn.net/luckyxiaoqiang/article/details/7393134 轻松搞定面试中的链表题目
* http://www.cnblogs.com/jax/archive/2009/12/11/1621504.html 算法大全（1）单链表
原文：http://blog.csdn.net/imabluefish/article/details/39267101