Impression of Week 8

We have started to discuss Linked List last week.  It takes me a little while to understand the linked list. It's a little confusing because there are two different class defined for Linked List. First is Linked List class and second is LLNode class. LinkedList class has attributes front, back, size. LLNode class has attributes value, nxt. When I writing the codes, I often mixed up those two classes and their attributes. To summary the characteristics of LinkedList, LinkedList is a list contains LLNodes, and with each node containing both data and a reference to the next node in the list. What is the advantage of using Linked List ? From the lecture codes, I notice that we can very easily append, add, delete, and insert any data into the list. In another words, when we create a data structure and beginning, linked list allows us many flexibility for future data rearrangement.

As I said, the Linked List contains Nodes, and each node has a data. In the lecture we apply self.value to call the data. To get the next Nodes, we use self.nxt. However, LLNode doesn't have attribute that give us the value of previous one, this why I find a great difficulty of doing lab 7. In one question, we need to insert a data before some specific position.

My strategy is that

first, we check is the v2 is in the first index of Linked List. My code is

if not, I start to check check every value in the list until we reach v2, but the point is once we reach v2, we know the index of v2, let say its index is i, and we want to add v1 at index i-1, but LLNode doesn't have the attribute of looking for its previous value (it only have the attribute of looking next value).

In that case, I have to keep tracking two values. Every time when we check if the current node value equals to v2, we have to also remember the previous node value and make is keep moving along so that we don't lose the track of it

Here is my final solution: