--- title: Eboard 39 Merge Sort number: 39 section: eboards held: 2017-12-01 --- CSC 151.03, Class 39: Merge Sort ================================= _Overview_ * Preliminaries * Notes and news * Upcoming work * Extra credit * Exam stuff * Questions * Quiz * Lab * Debrief ### News / Etc. * I hope to have tentative project grades to you by Monday (ignoring the presentation component). * We will discuss the form of the final next Monday. * I plan to have all your grades to you Monday of finals week. ### Upcoming work * [Writeup for class 38](../writeups/writeup38) due Friday at 10:30 p.m. * Exercise 5 * To: * Subject: CSC 151.03 Writeup 38 (YOUR NAMES) * *Due to a power failure, there is no writeup for class 39.* * If there were, it would have been Exercise 4f, 4g, 4h. * [Exam 4](../exams/exam04) * Prologue due Friday * Exam due Tuesday * Cover sheets due Wednesday * Epilogues due Wednesday. * No more readings. * No more quizzes (after today). * Project presentations on Wednesday. ### Extra credit (Academic/Artistic) * CS Extras Thursday: Summer opportunities in CS. ### Extra credit (Peer) * One acts Friday at 8pm and Saturday at 2pm and 8pm and Sunday at 2pm. * Wednesday at 4pm, Dance Projects in the Wall. * Piano Recitals, Dec. 8 at I'm not sure in SL. ### Extra credit (Misc) * Mental Health Campus Resource Fair. TODAY at 4pm in JRC 209. * Newtown movie Tuesday night. * Newtown was an act of extreme violence * Whoops! Your exams are due on Tuesday night. * If you see the movie, you can have an extra day on Exam 4. ### Other good things * Swim meet this weekend. (Friday 6-9 or so; Saturday 9-5 or so.) * YGB concert Saturday at 2p.m. * Composition class concert tonight at 7:00 p.m. * Jazz Ensemble Concert Friday at 7:30 p.m. * Chamber Ensembles Saturday at 4:00 p.m. * Collegium Concert Sunday at 2:00 p.m. ### Notes on exam 4 I have responded to most of the prologues that I received by 8 am this morning. Here are some common notes. Problem 1 * You can't just add counters or use the debugger, since many of the "expensive" procedures are built in. * Hence, you'll need to think about which procedures are "slow" (in that they lo ok at the whole list). * You may want to write down on paper the procedures each calls and think about wheth er each is "fast" or "slow". Problem 2 * I'd recommend direct recursion (without an accompanying "tally"). * I'd recommend that you use `pair?` rather than `list?` to check whether something is a sublist. (We did say that the input was well formed.) Problem 3 * No changing the vector. * No using vector append. * No using lists. * Good: Count the number of elements that meet the predicate. Then build the vector. Then copy. Problem 4 * Remember that you need to use binary search. * "use binary search" means "use the approach" not "call the procedure" * Do not change the vector. Problem 5 * The hard part of the problem is part e. * You need to write about this problem even if you decide not to do it. * We use `list-append` to make it easier to track costs. Other * The most common answer to Q3: "I'm going to do problem 6 because I enjoy whatz itdos and dislike trees." * The second most common answer: "I don't really like whatzitdos, but I like tre es even less." ### Questions (on the exam or other) Do you realize that the indentation is wrong on problem 1? : I do now. Do you owe AK an apology? : Yes. : "PLEASE! In the interest of safety, the use of rollerblades or scooters is *forbidden* in academic buildings." : But, from now on, the use of any wheeled vehicle on the 3rd floor of Noyce is discouraged, except if it is necessary. Quiz ---- * If you finish early, review the self-checks from the reading. * Bonus one point question: When we make CW scoop out all of the water in the Noyce elbow using a teaspoon, approximately how many gallons will they need to remove? * Simplified version: Approximately how many gallons of water are now in the Noyce Elbow (or were there at 1pm.)? Lab --- * There should be six parts (a-f) in exercise 1. Please reload if you don't see all six parts. * Then reload about five more times fo rall of the other things I forgot to fix. Sorry! * I have tenure, it's okay if I admit mistakes on a public web site. * Writeup 4f, 4g, and 4h. Debrief -------