tree 专栏

算法演绎:

http://code.jcly.twbbs.org/docs/algorithm/%E6%BC%94%E7%AE%97%E6%B3%95%E7%AD%86%E8%A8%98/www.csie.ntnu.edu.tw/_u91029/Tree.html

 

Top-Down Approach

and A Bottom-up Approach 

http://leetcode.com/2011/07/lowest-common-ancestor-of-a-binary-tree-part-i.html