CSC 207.01 2019S, Class 40: Wrapup

Overview

• Preliminaries
  • Notes and news
  • Upcoming work
  • Extra credit
  • Final PSA
  • Questions
• The subject matter(s) of the course
• Course evaluation
• Final notes
• Notes on the final

Preliminaries

News / Etc.

• Sit where you would like.
• I’m working on getting grades to you as soon as I can. I’ll try to have all grades in by Tuesday. (May not include HW8.)
• I’ve finished grading all of the “on time” exam 2’s. I’ll return those at the end of class. (I don’t want better EOCEs for high grades, or worse EOCEs for low grades.)
• There are still some people who have not turned in exam 2. Please do not discuss it with anyone. (If you want to discuss it with someone, please check with me first to ensure that both of you have turned it in.)
• Review sessions for final: TBD. Tentatively Wednesday.
• Solution to quiz grading issue: 10% of your grade is the largest of (a) your quiz grade, (b) your average exam grade, (c) your grade on the final.

Upcoming work

• Final exam: 9am or 2pm, Thursday or Friday of finals week.
  • Let me know which of the four times you plan to take the final.

Extra credit

Extra credit (Academic/Artistic)

Extra credit (Peer)

• Today May 10, 2pm, Science 2022, An Exploration of Torsion of Elliptic Curves over Cubic and Quartic Fields.
• Tonight May 10, 7:30pm, Voice Recital, Students of N. Miguel
• New May 12, 6:30pm, A Capella Concert in the Rotunda

Extra credit (Wellness)

Extra credit (Wellness, Regular)

• Any organized exercise. (See previous eboards for a list.)
• 60 minutes of some solitary self-care activities that are unrelated to academics or work. Your email reflection must explain how the activity contributed to your wellness.
• 60 minutes of some shared self-care activity with friends. Your email reflection must explain how the activity contributed to your wellness.

Extra credit (Misc)

Other good things

• Tonight Dance MAP, 4:30 pm, Flanagan

Final PSA of the semester

• Don’t let the stress of finals’ week negatively affect you.
  • Get enough sleep.
  • If you decide to shut off your brain with substances, do so in moderation.
  • Don’t let academic honesty become an issue; our decision-making becomes less good at this time of the semester.
• Consent is essential.

Questions

How long did people spend on exam 2?

Here’s the data for those who turned it in on time.

        P1      P2      P3      P4      Total   (Hours)
Min     30      30      30      30      175     2.9
Max     240     210     360     210     900     15.0
Ave     114     98      119     96      428     7.1
Median  99      98      98      90      368     6

Why the variance?

The person on the low end writes a lot of code for fun. The one on the high end spent three hours on a bug having to do with == vs equals.

Will there be questions on object-oriented programming and design on the final?

I’m not inclined to add a sixth question. But I am likely to include to OOP and design issues in other questions.

The subject matter(s) of the course

I thought it would be useful to get an overview of what we’ve learned on the board. In part, that will help you study for the final.

In addition, the end-of-course evaluations have five questions that read “blah blah blah helped me understand the subject matter of the course”. When we first started using College-wide EOCEs, I asked “How will students know what the subject matter of the class is? After all, students call CSC 151 ‘The Scheme Course’, even though our primary focus is functional problem solving, and CSC 152 ‘The Java Course’, even though its focus is algorithms and data structures.” The response was “You can tell them.” But that’s not my style.

So we’re going to collaboratively develop a list of things you may have learned in CSC 207 this semester. I tend to group them into categories.

• I’ll describe the categories and give an example for each.
• I’ll give you some time to come up with suggestions. (Each group should come up with a few for each category.)
• We’ll get as many on the board as we can. Each group should make sure to add at least one to each category.
• We’ll talk through them for a bit.
• I’ll probably take photos and record them in the eboard at a later date.

ADTs

• E.g., Lists (things you can iterate)
• PUM - Philosophy, Use Case, Methods - A way to think about ADT Design
• Stacks
• Trees
• Queues
• Graphs
• (Block chain)?
• Maps
• Heaps
• Priority Queues

Data structures

• E.g., ArrayBasedLists (lists stored in arrays)
• LIA - Layout, Implementation, Analysis
• Ways to organize info in a DS: Linked structures and array-based structures
• Heap (binary heap)
• Hash tables (probing and chained)
• Arrays
• Linked lists (singly, doubly, circularly, blockchainy)
• Tries
• Binary search treees
• SkipLists
• Implementations of graphs (adjacency matrices, edge lists)
• Sorted lists / arrays
• Array based implementations of basic linear structures
• Linked implementations of basic linear structures

Adjacency matrices:

    v1 v2 v3 v4 v4
v1
v2
v3
v4

Algorithms

• E.g., Quicksort
• Sorts
  • Merge sort (bottom up and top-down)
  • Bubble sort (in some cases)
  • Heap sort
  • Selection sort
• Graph algorithms
  • Dijkstra’s
  • Prim’s
  • Kruskal’s
• Traversal (tree and graph)
• Dutch national flag
• Partition
• Some related to individual data structures
  • E.g., remove from BSTs, add/remove from probed hash tables
• Algorithm techniques
  • Greed
  • Deep recursion (tree recursion)
  • Simulating recursion with stacks
  • Brute force

Merge sort

• Approach one (top-down): Divide into two halves, sort halves, merge together
• Approach two (bottom-up): Merge neighboring values into sorted pairs, merge sorted pairs into sorted four-tuples, merge sorted quadruples into sorted octuples, … (Iterative, rather than recursive.)
  • If Sam remembers correctly, a variant of this is part of the legendary timsort.

Algorithm analysis

• E.g., Big-O notation, formalized
• Loop invariants
• Modeling costs of operations
• Recurrence relations
• Really hand-wavy proof by induction
• Some important sums
  • (1 + 2 + 3 + … n) = n(n+1)/2
  • (1 + 2 + 4 + 8 + … 2^n) = 2^(n+1) - 1
  • (1 + 1/2 + 1/4 + 1/8 + …) = 2, more or less
• Rules of big O
  • Transitivity
  • Dominance

Object-oriented design

• E.g., The Iterator pattern
• Inheritance - Code reuse through “A is a B”
• Parameteric polymorphism - Code reuse through parameterized types
• Encapsulation
• Subtype polymorphism - Code reuse through functions
• Patterns: Wrappers

Software development

• E.g., Git basics
• Debugging in Eclipse & “sometimes print statements are better”
• Dealing with crappy software (e.g., “String is not visible”)
• Documentation
• Packages and project structure
• Testing & experimenting
• Putting stuff in tarballs
• Code reading
• Standard styles

Java

• E.g., Anonymous inner classes
• Generics - An implementation of parametric polymorphism
• “Java is your nanny” - Dealing with a language that doesn’t trust you.
• Functional programming in Java
• Exceptions
• Testing with JUnit
• Interfaces
• Thinking with references (yay state)
• Flush your output

Broader skills

• E.g., “Thinking on your feet”
• E.g., Working with others
• E.g., Coping with too much stress and work (i.e., time management)
  • Perserverence
• How to collaborate on stupid tasks when the instructor tells you to do so.
• Reinforcement of general problem solving skills.
• Ways to explain complex things (or at least practice doing so) (or “how not to” from Sam’s examples)
• Reading academic papers and extracting key issues

Anything else

• Some faculty are softies and will give almost arbitrary extnesions
• E.g., Drawing can help you understand structures and state
  • Diagramming data structures
  • Diagramming stack and heap
• Real-world applications of computing
• Oxymorons (Sam’s jokes)
• It’s not enough to understand the big picture; you have to get the details right.

Course evaluation

Evaluation forms may be found at https://grinnell.smartevals.com.

End-of-course ratings enable you to give responsible feedback for your professors, and the information you provide enters into future contract reviews. The agree/disagree responses will be tallied to produce frequency reports. The instructor will be able to review your unidentified comments within the electronic course evaluation system. Please note that the scale starts with “Strongly Disagree” at the top. Be careful not to inadvertently reverse your responses. Please provide comments but do not write your name in the comment boxes. Instructors receive the unidentified, completed forms only after grades have been submitted to the registrar.

Final notes

Notes on the final (if time)