Today’s Agenda Linked Lists Double ended Linked Lists Doubly Linked Lists CS2336: Computer...

Today’s Agenda

Linked Lists

Double ended Linked Lists

Doubly Linked Lists

CS2336: Computer Science II

Linked List

Made up of Nodes

Each node has An item A reference to next node in the list


item

nextl1

item

nextl2

item

nextl3

7 0 6

Advantages over array

Inserting item into middle of linkedList takes constant time if you have reference to the node

The list can keep growing until memory runs out


Inserting an item

Insert a new item immediately after “this” node. insertAfter method


item

nextl1

item

nextl2

item

nextl3

7 0 6

item

next

3

Disadvantages over array

Finding the nth item of a linkedList takes O(n) because it is proportional to size of the list. But in array you can do it in constant time

A lot of data structures that we will see in this course are trying to find a solution that works quickly in all the different cases both finding and inserting new items


Find nth position

First we check , if the position is equal to 1 then we find the solution and return this

Then we check if the position is less than 1 or our list is empty (next is null) , so return null

If none of the above, then we use recursion. The idea is that if I jump forward one node or I jump

to the next reference then I can call nth recursively on that node and the position is one less.


This

4th

This 3th

Linklist

ContactName List Example


Double ended linked list

Think about a neighborhood with neighbors

First we create neighbor object

Double ended has both reference to the first and the last link in the list

Firstlink and lastlink

Add new neighbor to the beginning of the list

Add new neighbor to the end of the list


Doubly linked list

Unlike the other list that they only had value next and they could only go forward, we have value previous so we can go backward too.

Add after a specific key

Add on order


Today’s Agenda Linked Lists Double ended Linked Lists Doubly Linked Lists CS2336: Computer...

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