摘要：
http://www.cnblogs.com/zhengyun_ustc/p/55solution2.html http://wenku.baidu.com/link?url=P756ZrmasJTKvzw9MJB5jwTreZjyCWzMJPY-_R9hOGPr3hYrLDv0QUCxl4mGrr 阅读全文
摘要：
http://www.cnblogs.com/carekee/articles/1854674.html http://www.cnblogs.com/xdp-gacl/p/3926848.html 阅读全文