滴滴算法大赛算法解决过程 - 方案设计
https://www.cnblogs.com/TextEditor/p/5527124.html
http://www.codesnippet.info/Article/Index?ArticleId=00000038
http://www.jianshu.com/p/4140be00d4e3
GBDT算法
http://www.doc88.com/p-6941533630446.html
PA和OD矩阵
http://blog.sina.com.cn/s/blog_6827755d0101b4c1.html