Recursion continued

Cheers, everybody! Reading Week is coming!

Before taking a good rest, I would like to do a brief review for what we've talked about this week.

We learned a new concept "tree" during the lecture. Below is an example of a tree:

There are a lot of terminologies associated with Tree . As a reminder, a tree has root, nodes, edges, height, leaves and subtree. And there are paths and lengths of those paths. The definitions of those terminologies are explicitly explained in Week 5 slides posted on the course website, and I will not present it in this post.So far, the terminologies are fairly easy to understand.




Later, we were given a few examples of implementation of Tree methods, like the counting of leaves and height of the tree, looking for the maximum number of branching factors, determining whether the tree contains a certain value. In all these methods, we used  recursion. First, we need to take a look at the base case, that is when the case is simple enough not to require recursion. Then comes the real challenge. We need to write codes to examine the whole tree, that is to go through every node(in some cases, we just go through some particular nodes) in a tree and call the function on it. To make it easier, before writing codes, we traced smaller trees in class. Then we combined the smaller instances to get a solution which worked for the entire Tree.

In this week's lab,  we practiced using recursion in Tree. Though I understood the course materials, I found it hard to write the recursion myself. I got stuck with a problem in the handout for almost thirty minutes, and felt really bad at that moment. Fortunately, my TA was really nice. I asked him for help, with great patience, he guided me to trace smaller examples and explained the whole thing clearly. Now I feel much more comfortable with writing recursions.  But, I'm far from doing without problems,  I still need a lot of practice and plenty of time to try to catch up. The coming reading week seems a good opportunity for me. Hope I will get better with some additional practice. 


Wish everyone a good reading week! :)