The 2nd Monitor

Officially, there are no guidelines, but in my opinion:

	public static SudokuBoard classicWith3x3Boxes() {
		return sizeAndBoxes(DEFAULT_SIZE, DEFAULT_SIZE, DEFAULT_SIZE / BOX_SIZE, DEFAULT_SIZE / BOX_SIZE);
	}

Map<String, String> map = Stream.of("A,1,!","B,2,@","C,3,#","D,4,$","E,5,%")
        .map(line -> line.split(","))
        .collect(Collectors.toMap(
                array -> array[0],
                array -> array[1]
        ));
map.forEach((k, v) -> System.out.println("Key = " + k + " / Value = " + v));

This looks readable to me

@SimonAndréForsberg Only for a classic board? Did you generalise it even more?

Q: SudokuSharp Solver with advanced features

@skiwi You haven't seen the Samurai method I assume?

Take a look at the pictures in my C# question to see which Sudokus the code can solve

16

Even though it's the first time I'm writing something this "big", it feels like I know C# quite good. It's been nice to learn LINQ also and I am very impressed by the features, and perhaps I have overused it here (if it's possible to do that). SudokuFactory: Contains static methods to create so...

@rolfl I find this funny: "If you include the parallelism, then a fork-join process is right. Not a stream.

My Attempt

I am not claiming this is right, or best practice (...)" :)

4:05 PM

They all look like sets of 9 boxes, unless I am mistaken?

The Nonomino doesn't have classic 3x3 layout of 3x3 boxes, but instead has a 'squiggly' kind of 'boxes'.

I think I sense confusion

They all look like sets of 9 tiles, unelss I am mistaken?

Might be worded more appropiate

Well, yes. That's correct. Although it doesn't necessarily have to be 9.

In any future sudoku the tiles themselves could even be disjoint, as long as one set consists of 9 tiles and is correct only if it has the numbers 1 through 9 distinct?

Then what I just said, but then with X tiles?

If I understand you correctly, yes.

Q: how to reduce the complexity of the given code?

4:10 PM

0

Below is my solution for this 'Team Split' problem. In summary, the problem is to find relative strength of 2 teams by finding the difference between their total strength (individual strengths can be found using a quadraric expression of form ax2+bx+c) The solution in Java manages to solve the ...

java

Btw another point, it would be better if you put all class variables at the top imo in SudokuBoard

^ I assume this is an algorithm problem; not a coding problem.

Oh well.

In all honesty, I find your code quite illogical, I would expect a SudokuBoard to have a width, a height, and a list of a set (or list) of tiles, where the set of tiles woudl be called a group

@skiwi SudokuBoard does have a width, height and a set of SudokuRules. A SudokuRule is a set of tiles.

@ChrisW Do you consider algorithm problems to be less on-topic??

@SimonAndréForsberg Then I think the SudokuRule name is a bit weird... As I'd expect it to be a rule, but it's a set of boxes.

4:22 PM

@skiwi It's a set of tiles (or is a box the same as a tile?). And it enforces a constraint on the board, hence the name rule.

For the rst I think it should only be accepting a Collection and not a list in the constructor

But it is a set of objects...

SudokuRule(Collection<SudokuTile> tiles, String description) { <--- looks like a Collection to me

that one yes

SudokuRule(Stream<SudokuTile> tiles, String description) {, this one looks like a Stream to me :p

@SimonAndréForsberg Choosing an algorithm is a pre-coding activity. If it is an algorithm issue, the only reason for doing a code-review is to reverse-engineer the algorithm in order to choose a better one.

@ChrisW So do you think that the question off-topic??

4:25 PM

I'm sorry if I do not go to deeply onto the possible stream issue in your code, but I got some other doubts first

So, answering the question means solving the puzzle (picking the good algorithm), not reviewing the code.

Well, I see plenty of comments that can be said about the code as well.

@skiwi Yes, that Stream constructor I am not so sure about myself, and I don't think @rolfl likes it much either.

@SimonAndréForsberg I have doubts on your `SudokoFactory`, in some sudoko formats it creates the board ánd assigns the groups to the boards.
In other formats (the simple one), the board needs to handle creating the groups itself.

@SimonAndréForsberg Possibly should be off-topic, but isn't: precedents say that if it contains source code then it's reviewable.

I find that a bit awkard

4:27 PM

@SimonAndréForsberg Yes but the OP may not care for those comments.

@ChrisW Even if the question is only about picking a better algorithm, I think it can be a good question. I think it should be perfectly on-topic. The worst part about this particular question/code is his horribly bad variable names.

Doesn't matter if the OP cares about them or not, we care about them.

@skiwi That is a very good point.

I think the structure needs to be redone quite a lot, I'd expect a SudokuSolver somewhere... But I don't see it explicitely in your code

The board takes care of the solving. It has a solve method.

A: Java 8 Effective Use of Multiple Streams

@skiwi - @SimonAndréForsberg - updated this answer with some code at the end:

10

Your code is odd in the sense that it is going to a lot of effort to calculate that 103 is 1000. I understand why you are doing it, but I took the liberty of changing the count() terminating function and replacing it with: StringBuilder sb = new StringBuilder(); ....... .forEachOrdered(prod ->...

@ChrisW I'm going to review his code... this might take an hour :)

4:32 PM

Why would it need to do? I'd expect a board to just hold its contents

By extracting the functions, it looks better.

@skiwi Because I wrote the code just to be a SudokuSolver, I wasn't planning on making a game out of it. And I was frustrated with Visual Studio when I wrote it so I didn't extract the solving much.

@SimonAndréForsberg Two problems I had with editing the question: choosing a better title; and the problem description being copyrighted.

@rolfl I find none of our(&OP) versions actually self-descriptive with the using streams

@SimonAndréForsberg And then... a game happened?

@skiwi The code I have for Sudoku is not 'playable'. Code for playing it could easily be added, but I didn't see the need to. I just wanted to solve sudokus.

4:36 PM

anyone know of a good Free Antivirus software that I can use on my computers?

I still think seperation is the way to go, but let's not discuss that further

@Malachi Avast!

No antivirus, they slow down your pc

@Malachi AVG?

@Malachi - AVG ...but is it still free?

4:38 PM

pcmag.com/article2/0,2817,2388652,00.asp this site says the highest score went to Avast

I don't think AVG is Free....

free.avg.com

I wouldn't use AVG or Avira myself, because they have proven to be slow as hell and slow down the pc... But that's just my opinion

Avast is free and lovely, it even has a nice voice saying "Avast virus database has been updated" :)

@rolfl i just found that one

@SimonAndréForsberg I randomly stumbled upon one method here:

4:40 PM

My experience is that AVG has a lot of false positives.

I think you are misusing forEach a bit :P

	void ResetSolutions() {
		Arrays.stream(tiles).forEach(
				arr -> Arrays.stream(arr)
						.forEach(tile -> tile.resetPossibles()));
                //vs
                rules.forEach(rule -> rule.forEach(SudokuTile::resetPossibles));
	}

i would probably have like 2-3 of them installed but not running and then pick a day of the week where I run them one after the other after updating them or something like that.

I added my version at the bottom under //vs

have one running non stop

I think know enough of the program to know if they do the same, but I suspect that tiles is about equal to all the tiles of all the rules combined?

After that change the program still runs, so the change must have had no impact!

(Cough bad Q&A)

4:42 PM

@skiwi Looping over each rule is unnecessary as one tile can be within any number of rules. By only looping over the 2D array I only perform it on each tile once.

Ah then forgot that code

For a regular classic Sudoku, there's 27 rules each containing 9 fields. So that's three times as many iterations.

Still I do not think you want to abuse .forEach for this

What code? I don't remember any code :)

@Malachi You would have 2-3 of what exactly?

Good :P

4:44 PM

Oh, hi @Nobody. I think I talked to you a lot yesterday when no one was around.

Q: Want to check if I am using PDO correctly

@SimonAndréForsberg: I feel I should coin a new meme that is "@SimonAndréForsberg ing" which means: pinging you unnecessarily

3

Stack Exchange

0

so today after few years of not programming in php I decided to go back, but to do so I need to change all mysql connections. So I want to check if I am using it good. So I used to write something like this: $user = clean($_COOKIE["Logged"]); $GameReg = mysql_fetch_array(mysql_query("SELECT * F...

mysql pdo

@Nobody Looking forward to it :)

@Nobody is looking forward to that.

@SimonAndréForsberg Pick your evils

	void ResetSolutions() {
		Arrays.stream(tiles).forEach(
				arr -> Arrays.stream(arr)
						.forEach(SudokuTile::resetPossibles));

                //vs

                for (SudokuTile[] tileArray : tiles) {
                    for (SudokuTile tile : tileArray) {
                        tile.resetPossibles();
                    }
                }

                //vs

               for (SudokuTile[] tileArray : tiles) {
                   Arrays.stream(tileArray).forEach(SudokuTile::resetPossibles);

but... there is a better way

so I got your approval to enter it into the meme list?

4:47 PM

What do you think about this?

	void ResetSolutions() {
            forEachTile(SudokuTile::resetPossibles);
	}

        void forEachTile(Consumer<SudokuTile> consumer) {
            for (SudokuTile[] tileArray : tiles) {
                for (SudokuTile tile : tileArray) {
                    consumer.accept(tile);
                }
            }
        }

@StackExchange How could the user forget about tagging it with PHP?

@Nobody It's not a meme yet... you'll have to do it a couple of times first :)

hm who can pin here in chat?

@skiwi Readable, but I'm not sure that forEachTile method would be used in other places? I actually used a good old for-loop at first but wanted to do it Java 8 style :)

@Nobody What do you want me to pin? Your message?

yep

also: writing it into the meme list might make it a self-fulfilling prophecy ^^

Done. Everyone with an italic username (room owners) has the ability to pin items.

4:50 PM

ahh good to know

@SimonAndréForsberg If you insist on Java 8 style I'd take the Consumers out of Java 8 instead of double forEach with Arrays.stream(), and to really warrant this approach it needs to be used on at least 2 places

what distinguishes a room owner? (besides the italic name)

@SimonAndréForsberg protection programs. if I had the money that is what i would want to do.

@Nobody The ability to pin/unpin and edit room feeds and description. That's about it I think.

ok and how to does one obtain this status?

creating the room I suppose but you did not, did you?

4:53 PM

AVG seems likie the better option between AVG and Avast, it comes with more. but i have to get going.

I will test one for a while and then test the other one, and then run the free trial out that I get with the computer

@Nobody An existing room owner can change the list of room owners, and if all previous owners are absent for a long while the system automatically chooses new owners. @Mat'sMug got promoted by the system a while ago and he added some regulars to the list

based on which criterion does the system do that?

Automatic appointment of room owners

If a reasonably active room has no owner, or none of the owners have been in the room for a certain time, a new owner may be automatically appointed, to ensure that there's somebody who can administrate.

The system will pick the room's most active user in this case and make them owner; this is announced via an automatic message. If the user does not want to be room owner, they can revoke ownership from themselves by going to the access tab on the room info page and setting their status back to “no special access”. Before they do this, they should find …

chat.stackexchange.com/faq

a thx @ChrisW

should have thought about the faq

btw do you support my meme proposal?

no

Status Update, 2014-03-23: It's no use! The percentages are barely budging. Although we have nearly doubled the number of ≥4k users since mid-Janurary, we're also gaining a lot of new avid users. The increased upvote activity has undoubtedly been beneficial, but I'm not convinced that this query is a useful metric of the vitality of the community.

5:11 PM

I wonder how much influx of people with OT question that never ask again there is on CR

especially compared to other sites

huh, I dug up some history:

Nov 25 '13 at 13:11, by Stack Exchange

retailcoder has been automatically appointed as owner of this room. (What does this mean?)

@rolfl I remember that as if it was yesterday

@Nobody "Avid users" ignores people with a rep of less than 150.

oh ok

But if the number of avid uses is constantly growing, it's hard to ensure everyone is endlessly promoted.

Yet apparently that's their definition of a healthy site.

5:20 PM

I feel the ordering in 200_success's welcome query should be changed accordingly

so that those show up first that are closest to crossing the boundaries (200 and 500 rep)

So who thinks my new answer helps establish my reputation as an ancient curmudgeon?

OldCurmudgeon, UK

546 2 12

java lock-free thread-safety loop multithreading best-practice c++

@JerryCoffin - bein a curmudgoen myself, I will point out I said this in my answer:

> A for-loop is the right thing for this construct (if it was not for the parallelism). If you include the parallelism, then a fork-join process is right. Not a stream.

@rolfl I refuse to settle for merely "old" -- "ancient" or bust...

@rolfl What you didn't point out though is that in this case, the parallelism almost certainly loses more than it gains. The time to spawn threads, or even dispatch to threads in a pool, almost certainly exceeds anything you could hope to gain from running such trivial computation in parallel.

I guess I didn't point that out explicitly either though. I should probably edit.

Latest Java zombie DOWN!

Although I couldn't find any particular speed issues in the code... mostly because he didn't mention which inputs caused the speed issue.

And I actually think his code is very fast. I don't see any special improvements.

I might have exaggerated a bit in my readability comments... but well...

Let's see what the comments and votes will be.

Hey @syb0rg

syb0rg

5:35 PM

@skiwi I like the new avatar.

@SimonAndréForsberg You made me want to create a Sudoku game/solver with Java 8 and Java FX 8

syb0rg

Hey @SimonAndréForsberg

thanks

now I am out of ammo

@skiwi That's the spirit :)

Q: I can read from /dev/null; how to fix it?

5:37 PM

I love how giving one Java 8 answer on SO gave me 130 rep today

Lol, from the hot network questions

55

I read the Wikipedia article on /dev/null and was playing around by moving files to /dev/null. For this I created a test_file and put some contents in it: $ touch test_file $ echo "This is written by Aditya" > test_file $ cat test_file This is written by Aditya Thereafter I tried to move the ...

udev

@skiwi: I wonder if there is something like a /dev/null measure to categorize your program's resilience against such unlikely things as reading some values from /dev/null

There was a prank played at university the one time where a user replaced /dev/random with a sequential number generator.

@rolfl And that is... bad?

We were all doing things like students now are doing, building games, etc.

All our numbers were 'wrong'.

you mean like this

dilbert.com/strips/comic/2001-10-25

5:44 PM

Logo turtles kept moving in spirals.

2

(that was a good one, the user had code something like:

mov random(10)
if (random(1)) turn left else turn right

every second number was odd.... ;-)

Ah... wow now I understand the impact :D

Is something like that even possible in Windows?

Another 'game' to play would be to replace /dev/yes

2

@skiwi Yes (though it's not nearly as easy).

Wait, dev/zero

Does for example Java also hook into the /dev/x 'things'?

5:50 PM

Basically, you need to replace the DLL that Windows uses to implement its random number generation. Windows tries to prevent its known DLLs from being overwritten, but with a little persistence (and administrator rights) it can be done.