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Algorithms and Data Structures
TEACH THAT
Lassie, what’s in this ADS2 course ? Will it be interesting?
woof!
Content
• linked lists• single/doubly-linked, • insert, delete, find, min, max, …
• stacks• push/pop/size• bracket matching, RP calculator
• queues• enqueue/dequeue/size• circular queue (in array)
• recursion• see above
• big O
Content
• trees• n-ary trees: representations & properties• binary trees
• representations & properties & traversals• binary search trees
• insert/find/delete/traverse/height …• AVL trees• heap
• insert/delete/sort• splay trees• red-black trees
Continued
Content
• skip lists• Sorting
• bubble/insert/sift sort• merge sort• quick sort• bucket sort (pigeon hole sort)• bead sort
• Dictionaries• maps and hash tables
• open and closed hashing
Continued
ContentContinued
• 5 pieces of practical work• 2 of above are assessed• exam• lab every 2nd week• woof
Algorithms&
Data Structures
Algorithms
&
Data Structures
Great!
my ADS2 website under construction
(permanently)I hate moodle
Home
News
The lectures
The lectures
code & api
Lots of code in there
DEMOS
demos
Links to interesting & useful stuff
exercises
Questions & Answers
Questions & Answers
… and now for something completely different!!!
Lassie, why are algorithms and data structures important?
Lassie, will there be anything in the course that is challenging and
exciting?
I just hope I get feedback, continuously
Lassie, will you teach us to “THINK LIKE A COMPUTER SCIENTIST”?
Lassie, honestly, I’m not that experienced as a programmer. Will you help us with our programming?
Will we use BIG data sets?
woof!
1st couple of lectures “Who cares?”
If someone was to teach you to drive a car would they:
1. explain how the internal combustion engine works2. take you through the intricacies of synchromesh gears3. fully independent suspension, spring rates, and dampers4. front and real wheel drive: pros and cons5. basic aerodynamics 6. …7. …
… or would they show you the knobs and levers and take you for a spin
Go for a spin
1st lecture … “Who cares?”
Who cares?Machines are getting
bigger, faster, cheaper … do efficient data
structures and algorithms really
matter?
An emotional attachment to algorithms and data structures
An empirical study using the IMDB
An emotional attachment to algorithms and data structures
An empirical study using the IMDB
An emotional attachment to algorithms and data structures
An empirical study using the IMDB
HashSet?
ArrayList?
woof
An emotional attachment to algorithms and data structures
An empirical study using the IMDB
An emotional attachment to algorithms and data structures
An empirical study using the IMDB
We could run this in the class for 1st three entries above
So? What was that about? This is 1st & 2nd lecture
Quickly/Immediately they get to see Alg & DS can have a dramatic effectWe use real dataWe use a big data setWe show that there is an empirical side to CSComputer Science is a Science
Okay, what’s next
The TSP challenge
It’s impossible to cover all the material we want to cover
So give them something that will draw them in …
Give them something that is fun …
The TSP challenge
100 Glasgow postal codes in a 5K radius
Find the shortest tour
not assessed, no marks, … a crappy trophy
Email me tour wheneverI will maintain website
Basic code with GUI on course website
Code is here
Data sets are here
Code is here
Our very own demo program
Our very own demo program
Our very own demo program
Your challenge is do write a method for the TSP class to find as short a route as possible round Glasgow. You have all
semester to do this.
That took about a week to develop
Furthest insertion algorithm used
Easy to add a solver
Students can do this if they want (no pressure)
Thanks SoCS for letting me do this
Footnote for all …
Some crappy prizes:
1. Green jacket2. Blue Riband3. Pint of milk at the Indy 5004. Victoria Cross5. A gold star6. …7. 4th year project prize
I am NOT kidding
next?
Instant feedback!!!
btree as an example
btree
btree
btree
btree
btree
btree
btree
btree
Ewe have to implement some of
the methods and test them
Any other examples Lassie?
Doubly Linked List
Any others
avlTree and emailOfDoom
avlTree and emailOfDoom
avlTree and emailOfDoom
Feedback?
Well, there are also programs that use your classes and methods and test them against
data sets, checks results are correct, complexity is within limits and gives you
“brownie” points. Richard’s seen this before. He could tell you more if you want.
What was this “THINK LIKE A COMPUTER SCIENTIST” stuff?
Count from zero?
I, being of sound mody and bind, herby swear that I will, on occasion, write java code in the class, that I will
explain what I am thinking and doing. I also swear that I will debug code in the class and I will explain what I am
thinking and what I am doing. I will try my best to explain what I think is good and what is bad as a Computer Programmer … as Almighty Dog is my
witness.
baaa!
An Example
Example of “Thinking Like a Computer Scientist”
I spent one day tracking down a bug in ADS2 code
I fixed it
No big deal
But wait. Why throw that day away?
Do something with it!
anatomy of a bug
anatomy of a bug
anatomy of a bug
AVL Trees
Anatomy of a bug
I wrote java code for the avl tree: the data structure, a test/demo programand managed to display it …
I felt … smug
smug
smugsmug
smug
smug
It was written all over me
… so smug that I just HAD to demo it to a friend/colleague …
Dr. Chris “unworthy” Unsworth
… and this is what happened
Calm down … think
Example
Example
Example
Example
So?
The sheep have a point dude.
This is what I hope to do
1. Capture the students’ interest2. Convince the class that studying/knowing/using ADS is worthwhile3. Teach students the basics of ADS & a wee bit more4. Develop students’ programming skills (and their programming appreciation)5. Give fast feedback6. Develop students’ programming skills (I already said that, didn’t I?)7. When appropriate, expose the thinking of a Computer Scientist8. Use realistic data sets where possible
Available from the gift shop now
