Week 6
Recursive Structures.
In this week, I learned some terminologies and structures of Trees. 
Tree is constructed by nodes. One node is distinguished as root, which is the biggest parent, and each non_root node has exactly one parent. 
Node with no children is called as leaf, and node with one or more children is called as internal node.

There are three ways to visit root and subtrees.
Pre-order traversal - visit root, then pre-order left subtree, then preorder right subtree.
In-order traversal - visit in-order left subtree, then root, the in-order right subtree.
Post-order traversal - visit post-order left subtree, then post-order right subtree, then root.

After the lecture, I played with the examples of Tree which the professor posted on the website and I understood the structures of the above three methods. Also I found the best method to move cheeses from first stool to the fourth stool with minimum moves and completed the Assignment 1.