Leetcode 236: Lowest common ancestor in binary tree

April 25, 2016

Study the code:
https://github.com/douglasleer/LeetCode-Java-Solutions/blob/master/236.lowest-common-ancestor-of-a-binary-tree.java

Julia's C# warm up practice:
1. using Stack class ToArray API, keep the iterator order - stack output order: (5/21/2016)
https://gist.github.com/jianminchen/2bec8a70ef520e715240a226c01c7371

Read Stack class APIs:
https://msdn.microsoft.com/en-us/library/415129w1(v=vs.110).aspx

2. Use List.AddRange(Stack), still keep the stack iterator order
https://gist.github.com/jianminchen/754f45023f60992211cb34bef6d6254f


Compared to Java Stack class APIs later.

Question and answer:

1. What do you learn through the study of the code?

The code is using Binary Tree post order traversal method, and then, to find node p and q common ancestor, work on the stack, get list of nodes from root node to p, same to q, and then, find the common ancestor.

Blog:
http://juliachencoding.blogspot.ca/2015/08/tree-algorithms-review.html

Review:
Post order traversal iterative
https://github.com/jianminchen/leetcode-tree/blob/master/TreeDemo.cs

Write a C# version using exactly same idea.