Come up and say hello! 1. CPSC 221: Algorithms and Data Structures Lecture #0: Introduction Steve Wolfman 2010W2 2.

Slides:



Advertisements
Similar presentations
Queues A waiting line that grows by adding elements to its end and shrinks by taking elements from its front Line at the grocery store Cars in traffic.
Advertisements

0 of 37 Stacks and Queues Lecture of 37 Abstract Data Types To use a method, need to know its essentials: signature and return type o additionally,
1 Queues (5.2) CSE 2011 Winter May Announcements York Programming Contest Link also available from.
Come up and say hello! 1. CPSC 221: Algorithms and Data Structures Lecture #0: Introduction Steve Wolfman 2011W2 2.
Come up and say hello! 1. CPSC 221: Algorithms and Data Structures Lecture #0: Introduction Steve Wolfman 2009W1 2.
Copyright © 2014, 2008 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Starting Out with C++ Early Objects Eighth Edition by Tony Gaddis,
CS 307 Fundamentals of Computer Science 1 Abstract Data Types many slides taken from Mike Scott, UT Austin.
CSE 326: Data Structures Introduction 1Data Structures - Introduction.
Come on down! Take and fill out a survey Get a copy of lecture slides Please sit in the first 5 rows!
Administrivia- Introduction CSE 373 Data Structures.
COMP171 Data Structures and Algorithm Qiang Yang Lecture 1 ( Fall 2006)
CSE 326: Data Structures Lecture #0 Introduction Steve Wolfman Winter Quarter 2000.
Stacks, Queues, and Deques
Come on down! Take and fill out a survey Get a copy of lecture slides Please sit in the first 5 rows!
CSE 326: Data Structures Lecture #0 Introduction Bart Niswonger Summer Quarter 2001.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Dan Grossman Fall 2013.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Lauren Milne Summer 2015.
CSE 373 Data Structures and Algorithms Lecture 2: Queues.
Data Structures and Programming.  Today:  Administrivia  Introduction to 225, Stacks  Course website: 
Data Structures Lecture 1: Introduction Azhar Maqsood NUST Institute of Information Technology (NIIT)
Come up and say hello! (Welcome!) 1. CPSC 221: Algorithms and Data Structures Lecture #0: Introduction Kendra Cooper 2014W1 2.
CSE332: Data Abstractions Lecture 1: Introduction; Stacks/Queues Tyler Robison Summer 2010.
Chapter 3 List Stacks and Queues. Data Structures Data structure is a representation of data and the operations allowed on that data. Data structure is.
Data Structures and Abstract Data Types "Get your data structures correct first, and the rest of the program will write itself." - David Jones.
CSCA48 Course Summary.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Nicki Dell Spring 2014.
COMP2012 Object-Oriented Programming and Data Structures Fall 2015.
1 Chapter 7 Stacks and Queues. 2 Stack ADT Recall that ADT is abstract data type, a set of data and a set of operations that act upon the data. In a stack,
Data Structures (part 2). Stacks An Everyday Example Your boss keeps bringing you important items to deal with and keeps saying: “Put that last ‘rush’
30 May Stacks (5.1) CSE 2011 Winter Stacks2 Abstract Data Types (ADTs) An abstract data type (ADT) is an abstraction of a data structure An.
CPSC 121: Models of Computation Unit 0 Introduction George Tsiknis Based on slides by Patrice Belleville and Steve Wolfman.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Kevin Quinn Fall 2015.
Stacks and Queues. 2 3 Runtime Efficiency efficiency: measure of computing resources used by code. can be relative to speed (time), memory (space), etc.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Catie Baker Spring 2015.
Stacks And Queues Chapter 18.
CS221: Algorithms and Data Structures Lecture #3 Mind Your Priority Queues Steve Wolfman 2014W1 1.
Nirmalya Roy School of Electrical Engineering and Computer Science Washington State University Cpt S 223 – Advanced Data Structures Course Introduction.
Starting Out with C++ Early Objects Seventh Edition by Tony Gaddis, Judy Walters, and Godfrey Muganda Chapter 18: Stacks and Queues.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Linda Shapiro Winter 2015.
Data Structures Chapter 6. Data Structure A data structure is a representation of data and the operations allowed on that data. Examples: 1.Array 2.Record.
CSE 373: Data Structures and Algorithms Lecture 2: Queues.
Course Info Instructor U.T. Nguyen Office: CSEB Office hours: Tuesday, 14:30-15:30 Thursday, 12:00-12:45 By.
Data Structures and Algorithms in Java AlaaEddin 2012.
CSE 326 More Lists, Stacks and Queues David Kaplan Dept of Computer Science & Engineering Autumn 2001.
Stacks & Queues CSC 172 SPRING 2002 LECTURE 4 Agenda  Stack  Definition  Implementation  Analysis  Queue  Definition  Implementation  Analysis.
0 of 36 Andries van Dam  /05/15 Reminder: TA Hour Policies If you hit a bug, you must be able to show significant effort of fixing it on your own.
3/3/20161 Stacks and Queues Introduction to Data Structures Ananda Gunawardena.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Aaron Bauer Winter 2014.
CSE373: Data Structures and Algorithms Lecture 1: Introduction; ADTs; Stacks/Queues Linda Shapiro Spring 2016.
1 Lecture 15: Big O Notation (Wednesday) Lecturer: Santokh Singh CompSci 105 SS 2005 Principles of Computer Science Test See Web for Details Don’t be deleted!
 In general, Queue is line of person waiting for their turn at some service counter like ticket window at cinema hall, at bus stand or at railway station.
March 27 – Course introductions; Adts; Stacks and Queues
CSE 373: Data Structures and Algorithms
Stacks and Queues.
Cinda Heeren / Geoffrey Tien
Week 15 – Monday CS221.
Cse 373 April 26th – Exam Review.
structures and their relationships." - Linus Torvalds
structures and their relationships." - Linus Torvalds
Introduction CSE 373 Data Structures.
Ben Lerner Summer Quarter 2007 Lecture 1
Stacks and Queues CLRS, Section 10.1.
Spring 2016 Richard Anderson Lecture 1
Stacks and Queues 1.
CSE 373 Data Structures Lecture 6
Administrivia- Introduction
Administrivia- Introduction
CSE 373 Data Structures Lecture 6
structures and their relationships." - Linus Torvalds
Presentation transcript:

Come up and say hello! 1

CPSC 221: Algorithms and Data Structures Lecture #0: Introduction Steve Wolfman 2010W2 2

Today’s Outline Administrative Cruft Overview of the Course Stacks Queues 3

Course Information Your Instructor: Steve Wolfman ICCS 239 Office hours: see website Other Instructor: Alan Hu TAs: Alan Long, Benj Israel, Essex Edwards, Haoyu Zhou, Joel Kitching, Kenny Wan, Koosha Khalvati, Mohamed El-Zohairy, Norman Huang, and Ziyu Wang TA Office hours: TBA; see website Texts: Epp Discrete Mathematics, Koffman C++ (But… feel free to get Epp 3 rd ed or alternate texts) 4

Course Policies No late work; may be flexible with advance notice Programming projects (~4) due 9PM on due date Written homework (~3) due 5PM on due date Grading –labs:5% –assignments:20% –midterm:30% –final:45% 5 Must pass the final to pass the course.

Collaboration READ the collaboration policy on the website. You have LOTS of freedom to collaborate! Use it to learn and have fun while doing it! Don’t violate the collaboration policy. There’s no point in doing so, and the penalties are so severe that just thinking about them causes babies to cry *. 6 *Almost anything causes babies to cry, actually, but the cheating penalties really are severe.

Course Mechanics 221 Web page: Matygo site: –What’s Matygo? Why are we using it? A startup classroom management system created by UBC CS graduates that looks extremely promising. We and CPSC 211 will be early adopters. Should be fun! Labs are in ICCS X350 –lab has SunRay thin clients: use the “Linux” logon All programming projects graded on UNIX/g++ 7

What is a Data Structure? data structure - 8

Observation All programs manipulate data –programs process, store, display, gather –data can be information, numbers, images, sound Each program must decide how to store and manipulate data Choice influences program at every level –execution speed –memory requirements –maintenance (debugging, extending, etc.) 9

Goals of the Course Become familiar with some of the fundamental data structures and algorithms in computer science Improve ability to solve problems abstractly –data structures and algorithms are the building blocks Improve ability to analyze your algorithms –prove correctness –gauge, compare, and improve time and space complexity Become modestly skilled with C++ and UNIX, but this is largely on your own! 10

What is an Abstract Data Type? Abstract Data Type (ADT) - 1) An opportunity for an acronym 2) Mathematical description of an object and the set of operations on the object 11

Data Structures as Algorithms Algorithm –A high level, language independent description of a step-by-step process for solving a problem Data Structure –A set of algorithms which implement an ADT 12

Why so many data structures? Ideal data structure: fast, elegant, memory efficient Generates tensions: –time vs. space –performance vs. elegance –generality vs. simplicity –one operation’s performance vs. another’s “Dictionary” ADT –list –binary search tree –AVL tree –Splay tree –B tree –Red-Black tree –hash table –… 13

Code Implementation Theoretically –abstract base class describes ADT –inherited implementations implement data structures –can change data structures transparently (to client code) Practice –different implementations sometimes suggest different interfaces (generality vs. simplicity) –performance of a data structure may influence form of client code (time vs. space, one operation vs. another) 14

ADT Presentation Algorithm Present an ADT Motivate with some applications Repeat until browned entirely through –develop a data structure for the ADT –analyze its properties efficiency correctness limitations ease of programming Contrast data structure’s strengths and weaknesses –understand when to use each one 15

Stack ADT Stack operations –create –destroy –push –pop –top –is_empty Stack property: if x is pushed before y is pushed, then x will be popped after y is popped LIFO: Last In First Out F EDCBAEDCBA B C D E F A 16

Stacks in Practice Function call stack Removing recursion Balancing symbols (parentheses) Evaluating Reverse Polish Notation Depth first search Java VM execution engine 17

Abstract Stack Example push R push O pop push T push A push T pop push E pop 18 In order, what letters are popped? (Can we tell, just from the ADT?)

Array Stack Data Structure S 0 size - 1 abcde void push(Object x) { assert(!is_full()) S[back] = x back++ } Object top() { assert(!is_empty()) return S[back - 1] } back Object pop() { assert(!is_empty()) back-- return S[back] } bool is_empty() { return back == 0 } bool is_full() { return back == size } 19 This is pseudocode. Do not correct my semicolons

Linked List Stack Data Structure edcba back void push(Object x) { temp = back back = new Node(x) back->next = temp } Object top() { assert(!is_empty()) return back->data } Object pop() { assert(!is_empty()) return_data = back->data temp = back back = back->next delete temp return return_data } bool is_empty() { return back == null } 20

Linked List Stack Data Structure void push(Object x) { temp = back back = new Node(x) back->next = temp } Object top() { assert(!is_empty()) return back->data } Object pop() { assert(!is_empty()) return_data = back->data temp = back back = back->next delete temp return return_data } bool is_empty() { return back == null } 21 What’s with the red text? edcba back

Queue ADT Queue operations –create –destroy –enqueue –dequeue –is_empty Queue property: if x is enqueued before y is enqueued, then x will be dequeued before y is dequeued. FIFO: First In First Out F E D C B enqueue dequeue GA 22

Applications of the Q Hold jobs for a printer Store packets on network routers Hold memory “freelists” Make waitlists fair Breadth first search 23

Abstract Q Example enqueue R enqueue O dequeue enqueue T enqueue A enqueue T dequeue enqueue E dequeue 24 In order, what letters are dequeued? (Can we tell, just from the ADT?)

Circular Array Q Data Structure void enqueue(Object x) { Q[back] = x back = (back + 1) % size } Object dequeue() { x = Q[front] front = (front + 1) % size return x } bcdef Q 0 size - 1 frontback bool is_empty() { return (front == back) } bool is_full() { return front == (back + 1) % size } 25

Circular Array Q Example enqueue R enqueue O dequeue enqueue T enqueue A enqueue T dequeue enqueue E dequeue 26 What are the final contents of the array?

Circular Array Q Example enqueue R enqueue O dequeue enqueue T enqueue A enqueue T dequeue enqueue E dequeue 27 What are the final contents of the array? Assuming we can distinguish full and empty (could add a boolean)…

Linked List Q Data Structure bcdef frontback void enqueue(Object x) { if (is_empty()) front = back = new Node(x) else back->next = new Node(x) back = back->next } Object dequeue() { assert(!is_empty) return_data = front->data temp = front front = front->next delete temp return return_data } bool is_empty() { return front == null } 28

Circular Array vs. Linked List 29

Data structures you should already know (a bit) Arrays Linked lists Trees Queues Stacks 30

To Do Check out the web page and Matygo Begin working through Chapters P and 1 of Koffman and Wolfgang (C++ background) Read sections , 5, and 6 except 6.4 of Koffman and Wolfgang (linked lists, stacks, and queues) 31

Coming Up Asymptotic Analysis First Lab (download and look over materials as soon as they’re posted!) Programming Project 1 (solving mazes with stacks and queues) 32