The Whiteboard

user55340

00:01

The guy asking about the Java div 3 method this morning... I really wanted to post a comment with:

public void div3(int start, int end) { IntStream.rangeClosed(start, end).mapToObj(v -> v % 3 == 0 ? v : "").forEach(System.out::println); }

and ask if that helped.

user55340

00:12

Could a mod please: remove the zone tag (5 questions), delete the post that was about to get deleted ( programmers.stackexchange.com/review/low-quality-posts/103587 ), and remove the "We're looking for long answers that provide some explanation and context" mod notice from programmers.stackexchange.com/questions/46252 - a historical lock isn't inappropriate but we should finish the cleaning that was underway when it was locked.

Robert Harvey

[Wonders why anyone would go to the trouble of implementing the IEnumerable<T> interface in a class, when it's much simpler just write a method that returns an IEnumerable<T>]

durron597

00:24

@MichaelT I asked him to lock that, I didn't know you were in the middle of messing with it.

user55340

@durron597 Its not a bad lock... just that there were a few open reviews and... well... that answer is crap. Other answers are crap too, but they weren't up for VLQ reviews.

durron597

@MichaelT I'm sure @ThomasOwens will be around to take care of it tomorrow.

user55340

Also, if we're going to try to get rid of the zone tag, its easier to that when you don't have to remember to go after locked posts.

durron597

@MichaelT You could add it as an answer to the STCI post.

user55340

@durron597 since there are only 5 posts, its almost as easy to finish them off ad hoc.

durron597

00:27

@MichaelT I know but if a mod needs to get involved...

user55340

The only open one has 4 close votes at this time.

durron597

You could also just flag the locked one again, right?

Oh, you can't flag historical lock questions, huh.

user55340

I would of if I could.

durron597

> You voted to close this question 22 hours ago

@RobertHarvey Are you still around to put the 5th vote on ^^^?

user55340

@durron597 he got it.

Robert Harvey

00:31

That question is a mess anyway. Who disagrees with quiet time for coding? Other than the "open cubicles" folks, nobody.

durron597

@RobertHarvey My boss's boss wants us to be nearby, but he's super loud especially when on the phone.

It's more important to be nearby than to have quiet time to code

user55340

I've got a cube, but the place can be easily overheard... and there's a project manager who sits on the other side of the major aisle from me who has a very...projecting voice. I have to wear headphones when he's talking.

Robert Harvey

Working with generics, I always wind up being too generic. I separated my BinaryTree class into a BinaryTree<K, V> and a Node<K, V>, but now I can't new Node<K, V>() from the Binary Tree because it doesn't know the actual type.

So now it looks like I'm going to have to do Activator.CreateInstance(TypeOf(K)) and Activator.CreateInstance(TypeOf(V))

No, that's not going to work, either.

André

that is .Net?

Robert Harvey

Yes.

Hmm, looks like a Factory method in the Node<K, V> class might work.

        public static Node<K, V> CreateInstance()
        {
            return new Node<K, V>();
        }

It compiles, anyway.

André

00:43

Can't help much, never coded anything with .net

Robert Harvey

And another one for the other constructor:

        public static Node<K, V> CreateInstance(K key, V value)
        {
            return new Node<K, V>(key, value);
        }

durron597

Out of CVs 0044 UTC. Nice.

Robert Harvey

Egad, that's so much boilerplate.

Ah, crap. It didn't work anyway. The Type Parameter chased me all the way back to the BinaryTree class.

user55340

@Snowman you know you need to try your hand over on Code Golf...

user55340

94

Q: Do you want to code a snowman?

Here is a simple ASCII art snowman: _===_ (.,.) ( : ) ( : ) Let's make him some friends. This will be the general pattern for our ASCII art snowpeople: HHHHH HHHHH X(LNR)Y X(TTT)Y (BBB) The leading spaces and the parentheses are always the same for all snowpeople. The different letters r...

durron597

00:53

I approve of this question. — Snowman May 7 at 4:42

user55340

@durron597 he still needs to do some golfing.

user55340

btw, you saw the name of the first storm of the season?

durron597

@MichaelT ?

user55340

cnn.com/2015/05/10/us/tropical-storm-ana - I wonder if the 5th is going to be Elsa.

Robert Harvey

I have no fsking idea how to do it.

user114359

01:12

@MichaelT No way. I am a fan of the programming puzzles but not code golf. The only way to compete is to learn an esoteric language that exists solely for golfing and is so mind-bendingly terse and convoluted that it makes Perl blush.

3

user55340

@Snowman I look at it as competing within each language rather than overall. You can post C# and golf that. Just because it isn't on the leaderboard for shortest overall doesn't mean that it isn't a good golfing.

user55340

You could even write it in Haskell if you wanted..

user55340

1

A: Largest and smallest values from concatenated integers

Haskell, 98 bytes import Data.List g=sort.map concat.permutations.words h i=unlines[g i!!0,last$g i] main=interact h Split input string at spaces, concatenate every permutation and sort. Print first and last element.

user55340

Look at the leaderboard snippet...

user55340

20

Q: Integer mark into grade

Given a positive integer (0 and above, no maximum), convert it into a grade following these rules: A = 100+ B = 90 - 99 C = 80 - 89 D = 70 - 79 E = 60 - 69 F = 59 and less. This felt a little boring, so make the grade a + if it's 7,8 or 9 and a - if it's 0,1 or 2. Ignore this for the...

code-golf

user55340

01:19

Sure, CJam has 33... but they also have entires for ><> (71), C (99), sed (74), Haskell (78), R (99)...

user114359

I just get put off by answers like this one:
iii0)?/:0({:'6'(@@+?/'{'01.
;$-o:'4'(?\'7'(?;'+'o
;o'A'\ \'-'o;o'F'\

user114359

WTF is that anyway? Sure, Fish is a golf language, I guess it just doesn't make sense to me

user55340

Thats one of the children of befunge... which is interesting in that realm.

user114359

I can understand some languages like Perl being more concise, but some of these languages are basically "each command is one character and does stuff that Golf challenges need" ending up as incomprehensible gibberish.

user55340

@Snowman Oh, let me find that language...

André

01:21

I do see why is fun, but I'm with @Snowman

user114359

If the challenge were "shortest program in a useful language" that would make sense to me.

user55340

Scriptling! esolangs.org/wiki/Sclipting

durron597

@Snowman But Java and C# have a huge disadvantage to, say, Ruby and python

user55340

丟낆녬닆묬긅덯댦롤긐

user114359

CJam, Fish, GolfScript... it is almost a challenge to invent the tersest language, not to write the shortest program.

user55340

01:22

That's hello world.

user55340

@Snowman Its getting your mind into that language that is the challenge... not the size.

user55340

There are different challenges running in code golf that different people appreciate.

user55340

There are some that are doing the pyth vs cjam challenge for given questions.

user55340

There are also those that are working in a non-esolang and trying to golf those.

user114359

@durron597 Since there can be only one winning answer, they favor those golfing languages.

user114359

01:24

See, now my goal is to come up with a golf challenge that those languages have a hard time with

user55340

@Snowman That is actually a very worthy challenge.

André

I'd try Sclipting

durron597

@Snowman I know that; code golf shouldn't have an accept button. meta.stackexchange.com/questions/254175/…

user114359

I can understand how golfing in C# or Java is boring but personally, this is my opinion, those golf-specific languages are boring and stupid too.

user55340

I like golfing in dc when the problem is applicable.

durron597

01:26

151

Q: We're no strangers to code golf, you know the rules, and so do I

Write the shortest program that prints the entire lyrics of "Never Gonna Give You Up" by Rick Astley. Rules: Must output the lyrics exactly as they appear in the above pastebin. Here's the raw dump: http://pastebin.com/raw.php?i=wwvdjvEj Cannot rely on any external resources - all lyrics must ...

code-golf kolmogorov-complexity

user55340

There are also the KoTH challenges that some people try their hands at.

user55340

codegolf.stackexchange.com/questions/tagged/king-of-the-hill

user55340

And I doubt there will ever be a golf language attempt at this one...

user55340

53

Q: "KNOT" or "NOT"?

Write a program that processes an ASCII art representation of a tangled string and decides whether or not it can be untangled into a simple loop. The tangle is represented using the characters - and | to represent horizontal and vertical segments, and + to represent corners. Places where the stri...

code-golf math

user114359

@durron597 That is a good one

user55340

01:28

I'm still trying to get my head around it.

user114359

So do I pay $55 for this or wait it out and pay half price in a few months? Mortal Kombat X - PlayStation 4

user114359

THAT is the true issue at hand

user55340

(aside, one of the things I do like about the cjam and pyth golfers is that they really do try to explain what is going on)

user55340

1

A: Rearranging a set of numbers into order

Pyth, 17 bytes uXGhaf>FT.:G2]Z)Q Switching items in a list is really expensive in Pyth. So here's a fun solution, that stretches the rules a little bit. It's probably not valid. Try it online: Pyth Compiler/Executor Explanation First of all, the time complexity of my code is O(n^3). But th...

user114359

@MichaelT That is another really interesting one

user55340

01:31

Sure, the golf answer is uXGhaf>FT.:G2]Z)Q

user55340

The explanation is:

user55340

                   implicit: Q = input list
u               Q  set G = Q, update G as long with the following statements,
                   until it stops changing:
         .:G2         all pairs (G[i],G[i+1])
     f>FT             filter for pairs T, where T[0] > T[1]
    a        ]Z       add to this list of pairs [0]
                      (ensures that the filtered list is always non-empty)
   h                  take the first element
 XG            )      translate G by this pair (switches the values T[0] with T[1])

user114359

You know what is really interesting? When someone throws a Brainfuck answer into a code golf competition. That is probably the most verbose esoteric language I have seen.

user55340

@Snowman I've got a math theory and old scientific american issue and have some starting code on it... but didn't get too far.

user114359

@MichaelT hell I'd be interested just to design the algorithm. Almost anything dealing with spatial reasoning can be interesting.

user55340

01:34

@Snowman Yep. Oh, for brainfuck, something 'fun' that some people do is write a brainfuck optimizer.

user55340

And then there's this one that will make @RobertHarvey's head explode...

user55340

15

Q: Convert Fractran into Brainfuck

Background Fractran is an esoteric Turing-complete programming language invented by John Conway. A Fractran program consists of an ordered list of fractions. The program starts by taking a single integer as input. Each iteration of the program, it searches the list for the first fraction such th...

code-golf brainfuck code-generation fractran

user55340

FRACTRAN

FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Conway. A FRACTRAN program is an ordered list of positive fractions together with an initial positive integer input n. The program is run by updating the integer n as follows: for the first fraction f in the list for which nf is an integer, replace n by nf repeat this rule until no fraction in the list produces an integer when multiplied by n, then halt. Conway gave an interesting formula for primes in FRACTRAN: Starting with n=2, this FRACTRAN program generates the following sequence of integers: 2...

user55340

$user image$

user55340

That's a prime number calculator in fractran.

André

01:37

sweet

user55340

It outputs (among other things) 4, 8, 32, 128, 2048, 8192, 131072...

user55340

which are all powers of 2... 2^2, 2^3, 2^5, 2^7, 2^11, 2^13, 2^17...

user55340

For which the exponent is a prime number.

durron597

@MichaelT esolangs.org/wiki/Fugue

user55340

9

A: Why is FRACTRAN turing complete?

For an imperative language to be Turing complete it must have: Conditional loop Arbitrary number of variables FRACTRAN is a language that is made up of a series of fractions that stores its data in the exponents of primes. Lets say you want to add two numbers: 2a3b becomes 5ab 455 11 ...

durron597

01:39

@MichaelT toothycat.net/~hologram/Turing/HowItWorks.html

user55340

Then here's another oddball 2d language... rail: github.com/mtolly/rail - esolangs.org/wiki/Rail

user55340

(that first link is a haskell rail to C compiler)

user55340

02:23

Two more delete votes on programmers.stackexchange.com/questions/64383/… and four more close votes on programmers.stackexchange.com/questions/103823/… (things I found while poking at quitting)

user114359

I was just going through the list of delete vote questions and voted for #1 already. I just added my VTC on #2 right now

Robert Harvey