http://andyzh1314.ycool.com/post.1050703.html
http://www.notonlysuccess.com/index.php/segment-tree-complete/
http://chuanwang66.iteye.com/blog/1418459
http://chuanwang66.iteye.com/blog/1489811
Top Coder - RMQ & LCA
http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=lowestCommonAncestor