INTRODUCTION TO DATA STRUCTURES AND ALGORITHMS Marcus Frean School of Engineering and Computer Science, Victoria University of Wellington COMP T2 Welcome

2 PEOPLE  Co-ordinator: Marcus Frean [Co227, ] Office hours: 9-11am Fridays  Lecturer: Thomas Kuhne [Co233, ] Office hours: TBA....  Senior Tutor: Zarinah Amin [Co343, ]   Course URL:  Class Rep:YOUR NAME HERE? 2

3 ADMINISTRATION  Prerequisite:  You should have PASSED comp 102 (or have been granted a prerequisite waiver)  If you failed comp 102, you can take it again (comp102 and comp103 offered both trimesters, but not summer)  If you got a ‘C’ in comp 102 you’re likely to find comp 103 very difficult 3

4 HELPING YOU SUCCEED 4

103 timetable 5 Lectures: Mon-Thurs-Fri 10am, in same room. Tutorials and Help desk: Being finalised this week. this  is “Weekly timetable”, on the course website’s side-bar

6 LECTURES  Slides  printouts provided in class  also on course webpage  I’m looking into video – should be fine  Goals:  Provide a framework for your learning  Provide explanations/demonstrations  SLIDES NOTES TEXTBOOK 6

7 TUTORIALS  Taken by a variety of students  Starting next week  various locations  What happens:  work with peers to understand the tricky bits  The tutor will set topical problems – you will work out answers, get feedback, discuss with the tutor and each other...  Our aim: help you to understand both lectures and assignments better 7

8 ASSIGNMENTS  Critical for your learning!  10 Assignments, total 20%  Assignments out: Thursdays in lecture  Assignments due: Friday of the following week, before 10am (submitted electronically)  There’s a hard deadline of 10am, because late assignments cannot be accepted once solutions are made available! 8

9 ASSIGNMENTS Some THEMES for the assignments:  Graphical editors: painting, diagrams, family trees..  Processing files of TEXT DATA: analysing data files, stories, web pages etc.  Simulations: programs that implement bits of REAL world  Do it yourself – NO pairing like comp102!  You can work in the ECS labs at all sorts of hours of day and night  Register on a lab computer to obtain a user login (if you haven’t already got one from 102) 9

10 HELP DESK  Intended for small groups, of about 1...  One-on-one help with assignment work.  Close to the labs but not in them: print out your code, highlight what you want to discuss.  Day/Time/Venue: To be announced 10

11 TEXT BOOK  JAVA FOUNDATIONS: Introduction to Program Design & Data Structures - by Lewis, DePasquale and Chase - 2 nd edition is best  SAME textbook as comp 102  COMPLEMENTS lectures and assignments (but we do not always follow the text closely) 11

12 WEB RESOURCES  FORUM:  Post questions  Collaborate and help each other  Tutors and Lecturers monitor and answer when appropriate  NO posting chunks of ANSWERS to assignments!  all the lecture notes and assignments  videos (soon)  links to Java reference material  tips on getting Java and BlueJ working at home  previous tests and exams 12

13 ASSESSMENT  10 Assignments[20%]  Two Tests[ = 30%] 45 mins, on Friday 9 th August, and Friday 20 th September.  Final Exam [50%] 3 hours, during exam period  Mandatory Requirements:  Submit reasonable attempt for at least 7 out of 10 Assignments (all submitted assignments may be used for borderline cases and aegrotats)  At least ‘C’ grade overall to PASS 13

14 PLAGIARISM UNACCEPTABLE  We want you to LEARN, TALK to each other, learn TOGETHER, and HELP each other, but PLAGIARISM is UNACCEPTABLE!  Got help from anybody other than lecturer or tutor ? STATE IT ON THE ASSIGNMENT!  Copied bits of code from anywhere other than lecture slides or textbook ? STATE IT ON THE ASSIGNMENT! 14

15 SAFETY in the LABS  Computer Labs are the most dangerous labs in the university  More people are injured at computer labs than in any other science lab!  Your computer at home is probably even more dangerous! AAAAAaaaaargh! OOS is rampant and debilitating  Read the POSTERS in the lab  See student health quickly if you get problems 15

16 QUICK RECAP  What was in comp 102?  Classes, Objects, Fields, Methods  Conditionals, Loops (if, if...else, for, while, do..while)  Using variables, reading input, writing, drawing  Algorithm design  Using GUI’s (Graphical User Interface)  Arrays, and using ArrayList Revise these concepts to get a head-start! 16

17 Some Basic Terms  Algorithm: step-by-step process to solve a problem (pseudocode: part code, part English)  Program: actual implementation of an algorithm in a programming language  Data Structure: the way data is structured or organized (example: Array)  Collection: an object that serves as a repository for other objects (like a “container”) 17

COLLECTIONS  Big chunks of real life involve what we could call Collections, and this is reflected in programs written to help real life:  Collections of books, music, photos, clothes,...  Organized in a way to ease access and use items  Some STANDARD types of Collections we use in our programs:  List, Set, Bag, Stack, Queue, Trees, Map 18

19 COLLECTIONS  Different structures  No structure – just a collection of values  Linear structure of values – order matters  Hierarchical structures  Different constraints for accessing elements  get, put, remove anywhere  get, put, remove only at the ends, or only at top (and so on). 19

WHAT CAN YOU EXPECT...  Using and understanding the current Java Collections Library  Creating your own Collections  How to add, remove, search, sort,... efficiently So this is what 103 is about:  The fundamental data structures of computer science  The crucial algorithms on those structures  Especially the efficiency of those algorithms 20

21 Course Overview – Part 1 Programming with Linear collections  Different Kinds of collections:  Lists, Sets, Bags, Maps, Stacks, Queues, Priority Queues  Implementing, using, sorting, and searching these Linear collections... 21

22 Course Overview – Part 2 Programming with Hierarchical collections  Building, traversing Tree-structured collections  Re-implementing linear collections  with binary search trees  with partially ordered trees  with hash tables 22

23 RECURRING THEMES  Good Design Choosing appropriate implementations How do you get it right first time ?  Efficiency How fast is it ? How much memory does it take ? Analysis and benchmarking 23