Yet Another Cycling Forum

Off Topic => The Pub => Arts and Entertainment => Topic started by: Wowbagger on 03 January, 2014, 06:40:28 pm

Title: Sudoku
Post by: Wowbagger on 03 January, 2014, 06:40:28 pm

I'm quite partial to the occasional puzzle but I wouldn't say I'm any good. I tend to do puzzles from the site http://www.websudoku.com and select any one of the four categories (Easy, Medium, Hard, Evil) depending upon how much time I've got. My average time on an "evil" puzzle is a little over 40 minutes.

I stumbled across a rather good sudoku solver a couple of days ago, http://www.sudokuwiki.org/sudoku.htm, which shows how it solves puzzles by eliminating the various numbers that are impossible, one step at a time. I found it very interesting that the solver employs up to 20 different strategies to eliminate numbers. I tried a few of the "evil' puzzles from websudoku.com and watched the solver at work. To solve an evil puzzle, it hardly ever has to use more than about the simplest 4 of the strategies available to it. I would imagine that this illustrates how much better at this kind of puzzle computers are than are humans.

I tried a "diabolical" puzzle from the solver's own stock and it was very interesting as such weird devices as "XY-wing" and "Simple colouring" were employed. Even though the logic was, apparently, laid out before me, it wasn't easy to see exactly what was going on.

Does anyone else have a dabble?

Title: Re: Sudoku
Post by: mattc on 03 January, 2014, 07:07:21 pm

I'm a little addicted to the "killer" variant. There are a lot more permutations than with the 'classic'.

I can't say solving these sorts of puzzles electronically appeals to me - I love paper-and-pencil, and scribbling notes in the squares and the margins. (So pretty much all my Sudokus are from The Times!)

Title: Re: Sudoku
Post by: Wowbagger on 03 January, 2014, 07:30:39 pm

I don't usually bother with notes - I hold the numbers in my head. That clearly limits me to the relatively simple solving techniques that have been revealed to me by the "solver": for some of the more advanced ones I think you would have to have all the possible numbers for each square pencilled in. With the amount of space you've got available in the average newspaper that's not really feasible.

Yesterday's Graun's puzzle (I actually bought a physical paper yesterday) claimed to be "hard" but I could do the lot without notes - just writing down the only possible answer as soon as it became obvious.

Title: Re: Sudoku
Post by: Si on 03 January, 2014, 08:14:31 pm

I used to do sudokus (I too was a note scribbler) but then turned to super-hanjie ........I find these a little more absorbing than your average sudoku because for me the sudoku is often a case of either doing it or not doing it but the SH I can keep wheedling away at all day, with one of the harder ones, and get there in the end.

But I now find that doing SHs in the evening results in headaches in the morning  ???

Title: Re: Sudoku
Post by: Gareth Rees on 03 January, 2014, 08:34:32 pm

Quote from: Wowbagger on 03 January, 2014, 06:40:28 pm

To solve an evil puzzle, it hardly ever has to use more than about the simplest 4 of the strategies available to it. I would imagine that this illustrates how much better at this kind of puzzle computers are than are humans.

Yes, that's pretty much the case, and it's worse than you think: by restricting itself to solving techniques that can be explained to humans, the computer is hobbling itself. The fastest algorithms for solving Sudokus (for example, Donald Knuth's "Algorithm X (http://lanl.arxiv.org/pdf/cs/0011047.pdf)") result in solutions that are utterly opaque to humans. Having written several (http://codereview.stackexchange.com/q/37415/11728) programs (http://garethrees.org/2007/06/10/zendoku-generation/) for setting and solving Sudokus, I've come to think that Sudokus are really best thought of as puzzles by computers for computers!

Title: Re: Sudoku
Post by: orienteer on 03 January, 2014, 08:54:43 pm

Doing the puzzles is the main reason I buy a paper (on a much-reduced price subscription), and I do them before reading the paper as a check my brain still works.

I used to write the possible numbers in and complete by a process of elimination, but can now do all but the very hardest without. I write the missing numbers on the outside of the grid against each row and column as a reminder, I can't hold them all in my head!

I also printed off some blank grids, so if I went wrong I could start again, but don't usually bother these days.

Title: Re: Sudoku
Post by: Charlotte on 04 January, 2014, 12:12:21 am

I prefer real ku.

Title: Re: Sudoku
Post by: Pickled Onion on 04 January, 2014, 09:31:30 am

Quote from: Wowbagger on 03 January, 2014, 07:30:39 pm

I don't usually bother with notes - I hold the numbers in my head. That clearly limits me to the relatively simple solving techniques that have been revealed to me by the "solver": for some of the more advanced ones I think you would have to have all the possible numbers for each square pencilled in. With the amount of space you've got available in the average newspaper that's not really feasible.

The trick for that is to use an imaginary 3x3 grid within the square and use dots to represent the possible numbers. I find standard sudoku unrewarding especially when they get easier towards the finish and end up thinking "so what?". Killer sudoku can be more interesting.

Title: Re: Sudoku
Post by: Wowbagger on 04 September, 2014, 11:57:13 pm

I ask the solvers here present to have a crack at this one:-

http://killersudokuonline.com/archives/2014/5/11

It defeated me this evening to the extent that I keyed it into the solver at sudokuwiki.org and it defeated that as well! Could be that the techniques required were too incomprehensible for a computer to explain to a cerebrally challenged sexuagenarian, as per Gareth's comment above?

The chunks that I couldn't unravel were the 15 and the 14 in the top left block, the 31 and the 14 in the bottom left block, and the 10 and the 17 in the bottom right block. It seemed to me that there was more than one solution but my brain was overheating by the time I had finished.

I try to avoid trial and error, but I resorted to that at the end and that still didn't help me.

Title: Re: Sudoku
Post by: Pippa on 05 September, 2014, 04:00:48 pm

I got there in the end but it did involve trial and error. I ended up with the same unravelled "chunks" as you.

For the bottom L square for the 31 and 14, I had one number in the 31 (a 7 from the usual sudoku rules). It was clear that the key was around the combination of 25 or 34 in the 14. So, unlike you keeping all the numbers in my brain, into each square I entered the possible numbers.

There were a couple in this bottom L square where there were only 2 choices; one of these was a choice between 2 and 8; I figured with 2 being key this would be a good place to start with the trial and error approach as it would probably unravel the puzzle (equally there was 4/6 choice which would have worked as well I suspect). And it did. I got the choice right first time (but that was a purely 50:50 chance) so I did check the other option as well, just to be sure there weren't 2 solutions; there weren't.

Title: Re: Sudoku
Post by: mattc on 05 September, 2014, 06:53:18 pm

Yup, same here. trial-n-error on the 14 being
1346
or
1258

<slides note-paper along desk to show workings to honoured opponent>

Nice site Wow - although I much prefer my scribbling-on-the-newspaper approach. It's very rare to have more than 3 options for a square, so there's usually space.

Title: Re: Sudoku
Post by: Wowbagger on 26 October, 2014, 04:28:54 pm

Quite please with myself today. Solved this

http://killersudokuonline.com/play.html?puzzle=D3s05ry3221&year=2014

with no guesses and no mistakes.

Title: Re: Sudoku
Post by: Wowbagger on 16 November, 2014, 08:25:47 pm

And another!

http://killersudokuonline.com/play.html?puzzle=D3s2now3242&year=2014

I still normally get stuck and guess on these harder ones. I don't think I guessed on this one, but there was a calculation at one point that I thought was logical and either it was or it was a lucky guess.

(click to show/hide)

It was in the bottom left hand corner block.

Title: Re: Sudoku
Post by: noggy on 19 November, 2014, 07:24:24 pm

I do one a week- Saturday Times Samurai 5 grids in one which I enjoy, when I don't make a mess of it

Suggested times for "difficult" are usually around 55 minutes.
I usually do it over two/three nights taking on average about 3 times as long in total
I must be slow and thicky :facepalm:

Title: Re: Sudoku
Post by: Wowbagger on 06 October, 2015, 05:45:52 pm

Another seeming ambiguity here.

http://killersudokuonline.com/iphone/player.html?puzzle=D352d6q3566&year=2015

I'd be grateful for comments.

(click to show/hide)

I have filled in every square, but cannot clear up the 12 in the top centre block, The 45 in the centre, The 20 in the bottom centre, the 16 in the bottom right, The 13 and the 16 in the centre right, And the 13 in the centre left. Although this puzzle is entitled "Easy", I find these headings quite misleading and can often solve the supposedly harder ones more quickly than the allegedly easier ones.

Title: Re: Sudoku
Post by: spesh on 06 October, 2015, 06:45:23 pm

(click to show/hide)

12 top centre is (left-to right) 9, 3 which ought to allow you to complete 20 bottom centre and part of 45 centre.

13 centre right has to be (top-to-bottom) 4, 9 which will complete 16 centre right and 16 bottom right. Everything else should fall into place from there.

Title: Re: Sudoku
Post by: Wowbagger on 06 October, 2015, 06:46:47 pm

I keyed what I' solved into the solver mentioned upthread and it claimed there were two solutions!

Title: Re: Sudoku
Post by: spesh on 06 October, 2015, 06:56:45 pm

My full solution:

(click to show/hide)

3 8 7 2 5 4 9 1 6
2 1 6 9 3 7 8 5 4
5 4 9 6 1 8 7 3 2
9 6 3 5 7 2 1 4 8
4 7 8 3 6 1 2 9 5
1 5 2 8 4 9 3 6 7
8 3 4 1 2 6 5 7 9
6 9 1 7 8 5 4 2 3
7 2 5 4 9 3 6 8 1

EDIT: The way I was working it, I couldn't see how there could be two solutions, unless when you get to the ambiguous state as described in your post, one tries the options in a different cell block to the ones I tried the alternatives for. And life's too short to try solving a killer sudoku more than once!  ;D

Title: Re: Sudoku
Post by: Wowbagger on 07 January, 2016, 10:35:28 pm

Either I am being especially dumb this evening or this is a lot harder than moderate!

http://www.killersudokuonline.com/play.html?puzzle=D2ksy103659&year=2016

Title: Re: Sudoku
Post by: Pickled Onion on 28 February, 2016, 03:38:50 pm

Quote from: Wowbagger on 07 January, 2016, 10:35:28 pm

Either I am being especially dumb this evening or this is a lot harder than moderate!

http://www.killersudokuonline.com/play.html?puzzle=D2ksy103659&year=2016

You're not, that was quite tricky - and not helped by there being more than one correct solution:

(click to show/hide)

(http://handsonit.co.uk/images/sudoku.png)

And only one was accepted as correct! Grrr.

Title: Re: Sudoku
Post by: Wowbagger on 28 February, 2016, 05:07:15 pm

That appears to have only one possible correct solution in my book: the bottom RH block of 9 has a 16 which already contains a 6 and a 2. The other number must be 8, so then you can solve the other three.

Title: Re: Sudoku
Post by: Pickled Onion on 28 February, 2016, 05:08:52 pm

Doh!  :facepalm:


 :-[ too much red wine...

Title: Re: Sudoku
Post by: ElyDave on 28 February, 2016, 08:16:19 pm

Not often these days, although I do like the Killer variants.

It's all about practice.  I once got to the point where I could consistently do about half-2/3 of the times cryptic crossword, no chance these days.

Title: Re: Sudoku
Post by: Basil on 28 February, 2016, 08:29:01 pm

I've always had difficulty with the killer version because I've never been sure if  you can use a number twice in a sum area if that area is across more than one block.

I've not explained that well.  Do you see what I'm asking?

Title: Re: Sudoku
Post by: spesh on 28 February, 2016, 09:04:11 pm

Quote from: Basil on 28 February, 2016, 08:29:01 pm

I've always had difficulty with the killer version because I've never been sure if  you can use a number twice in a sum area if that area is across more than one block.

Short answer is no, you can't. If you find yourself repeating a number inside a sum area, you've made a mistake somewhere.

Hope this helps.

Yesterday's killer Sudoku in the Times was singularly mis-named as "deadly" - they reckoned on 56 minutes, and I rattled it off in around 30, and that included catching and correcting a mistake. ;D

Title: Re: Sudoku
Post by: ElyDave on 29 February, 2016, 06:29:48 am

anyone else come across a non-unique solution?

I had one with 4 spaces left, two pairs of numbers say 3s and 4s which I could put in two combinations without affecting the validity of the answer.

Never seen that again.

Title: Re: Sudoku
Post by: arabella on 01 March, 2016, 06:44:22 pm

yes, but I couldn't say when.  a set of pairs that could go either way around.
usually if I have one I then resort to arithmetic and find there is in fact only one solution - but arithmetic ony an option if you are doing killer sudoku, which is why i prefer it to the normal kind - the normal sudoku you could substitite shapes for numbers and it'll still work.
(circle, oval, triangle, square, oblong, lozenge, star, pentagon, hexagon, for example)

Title: Re: Sudoku
Post by: Riggers on 03 March, 2016, 01:23:43 pm

I can't quite believe what I'm reading.

Title: Re: Sudoku
Post by: Wowbagger on 01 May, 2016, 08:31:01 pm

Tricky one today.

http://www.killersudokuonline.com/play.html?puzzle=D2kkas63774&year=2016

It seemed to be very easy initially, and I completed about half the puzzle in no time, but I really struggled with the second half.

Title: Re: Sudoku
Post by: Wowbagger on 02 June, 2020, 03:16:15 pm

Since the lockdown began, I have resumed solving the daily Killer Sudoku.

The website I frequent issues a number of puzzles each day. Their Monday puzzle is reckoned to be the easiest, and they gradually increase in difficulty through the week, Sunday's being the hardest. I don't normally have much trouble, although some of the tougher ones can have me racking my brains.

Today's was labelled "Easy" but I thought it was a right git.

https://www.killersudokuonline.com/play.html?puzzle=D2kmxyp5267&year=2020

Some chap called Andrew Stuart has written a rather good Sudoku Solver which I occasionally use to give me some hints. It's not that uncommon, with the harder puzzles, for his solver to run out of techniques before I do.

https://www.sudokuwiki.org/killersudoku.htm

Title: Re: Sudoku
Post by: SoreTween on 05 June, 2020, 09:30:53 pm

I'm badly out of practice but sodding hell! I must be over an hour in and I've not found my first solid number yet.  The Outrageous linked in reply #8 was a doddle compared to this Easy.

(don't like the 'check' feature on that site, it's too easy to accidentally cheat)

Title: Re: Sudoku
Post by: mattc on 05 June, 2020, 09:59:51 pm

Quote from: Wowbagger on 02 June, 2020, 03:16:15 pm

Since the lockdown began, I have resumed solving the daily Killer Sudoku.

The website I frequent issues a number of puzzles each day. Their Monday puzzle is reckoned to be the easiest, and they gradually increase in difficulty through the week, Sunday's being the hardest. I don't normally have much trouble, although some of the tougher ones can have me racking my brains.

Today's was labelled "Easy" but I thought it was a right git.

https://www.killersudokuonline.com/play.html?puzzle=D2kmxyp5267&year=2020

Nope, beats me! (I can do all the Times ones with a biro, any grade, although the hardest sometimes take me quite a long time to get going. I always have to scribble some notes somewhere. If I printed this out I could persevere for a bit longer, but I can't promise I'd get started. I don't really enjoy spending 30 minutes getting started; it's the Middle Game that's usually most fun.)

I would not call it "Easy".

Title: Re: Sudoku
Post by: SoreTween on 10 June, 2020, 09:35:00 am

Woot! Got there eventually.  Lack of practice wasn't a factor, that's a harder puzzle than I've ever persisted with before.  I did use the solver for two hints, both things I should have spotted (7 in row A early on, can't recall the other).

Stepping right through with the solver afterwards I find three things:
1) It makes a lot of use of innies & outies.  I must learn to spot those, I didn't know that trick.
2) The solver only used rules down to Killer combos (hard).  I used those as my primary weapon.
3) That means I'm not even at the stage of using all the 'tough' strategies so I have a great deal left to learn/figure out.

Yesterday' 'easy' (https://www.killersudokuonline.com/play.html?puzzle=D2hjxqt5274&year=2020), is.

Title: Re: Sudoku
Post by: Wowbagger on 10 June, 2020, 11:00:39 pm

The annoying thing about "innies & outies" is that you sometimes have to revisit them multiple times, each time narrowing down the possible range of numbers until you have eliminated all but the right answer(s). When you have to add up 4 rows or columns to find the difference between what is stated in the cages and 225, it is areal  test for your mental arithmetic. But I reckon that these are a good way to keep the brain active and (hopefully) keep the dementia fairy at bay.

It's got to the point that I can solve most puzzles in well under an hour now.

Title: Re: Sudoku
Post by: SoreTween on 13 June, 2020, 11:15:30 am

Have you looked at this week's Mind Bender (https://www.killersudokuonline.com/play.html?puzzle=W2x2j085273&year=2020)?  I'm stuck so I put it into the solver (https://www.sudokuwiki.org/killersudoku.htm).  I'm quite pleased that it too is stuck having made just one more elimination than me.

I can't see a cell that is key enough to be worth going down the guess route.

Set this cookie to go straight to that point:

(click to show/hide)

[{
   "Host raw": "http://www.killersudokuonline.com/",
   "Name raw": "values",
   "Path raw": "/",
   "Content raw": "11W2x2j085273-00s378901s378902s378903s612345604s612345605s345606s345607s612345608s612345610s612345611s612345612s52345613s612345614s645678915s645678920s612345621s612345622s52345623s645678924s645678926s51234527s7345678930s81234567831s81234567832s55678933s81234567834s7345678935s7345678936s7345678937s7345678943s81234567844s81234567845s81234567846s7345678947s7345678953s7345678954s7345678955s81234567856s4678957s7123456758s7123456760s81234567861s81234567862s612345663s81234567866s4678967s7123456768s645678970s81234567871s7345678972s7345678976s51234577s645678978s645678980s7345678981s7345678982s612345686s612345687s612345688s6123456",
   "Expires": "At the end of the session",
   "Expires raw": "0",
   "Send for": "Any type of connection",
   "Send for raw": "false",
   "HTTP only raw": "false",
   "SameSite raw": "no_restriction",
   "This domain only": "Valid for host only",
   "This domain only raw": "true",
   "Store raw": "firefox-default",
   "First Party Domain": ""
}]

Title: Re: Sudoku
Post by: Wowbagger on 13 June, 2020, 11:30:02 am

I did that a couple of days ago but my machine seems to have forgotten it.

I'll have another go. I did today's https://www.killersudokuonline.com/play.html?puzzle=D368c7k5278&year=2020 in about 45 minutes.

PS I don't know how to set a cookie...

Title: Re: Sudoku
Post by: Wowbagger on 13 June, 2020, 01:25:41 pm

(https://scontent-lhr8-1.xx.fbcdn.net/v/t1.0-9/104220663_2604333969885796_9091493167259271014_n.jpg?_nc_cat=107&_nc_sid=8024bb&_nc_ohc=ZpIRlwwAQ-AAX9zDDXB&_nc_ht=scontent-lhr8-1.xx&oh=588a16a0f6272daa4c794657eb0dab2d&oe=5F08DD1C)

Progress...

Title: Re: Sudoku
Post by: Wowbagger on 13 June, 2020, 01:28:36 pm

(https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/104242391_2604342856551574_96502205671357171_n.jpg?_nc_cat=105&_nc_sid=1480c5&_nc_ohc=gnKOAA7mjQoAX-3eYlR&_nc_ht=scontent-lht6-1.xx&oh=a408dfab2ec238400681742db197b231&oe=5F0C1DA0)

Title: Re: Sudoku
Post by: Wowbagger on 13 June, 2020, 02:18:46 pm

I got there in the end.

I think the trickiest bit initially was realising the limited number of possibilities in the top row, once you've got the 789 triple for the 24-cage starting on A1. All the rest must be one of 123456 and the cage of 6 cells totalling 39 must be made of 456789. That then limits the two squares A6 & A7 to 4, 5 and 6.

Later on there was the elimination of 7 from A1 and J1. That was dependent on realising that C1 is valued at 6. 6 aded to the 18 in the cage starting at E1 meant that neither of those squares could be 7.

Title: Re: Sudoku
Post by: SoreTween on 15 June, 2020, 08:59:47 pm

Quote from: Wowbagger on 13 June, 2020, 02:18:46 pm

I got there in the end.

I'm no further forward.

Quote from: Wowbagger on 13 June, 2020, 02:18:46 pm

I think the trickiest bit initially was realising the limited number of possibilities in the top row, once you've got the 789 triple for the 24-cage starting on A1. All the rest must be one of 123456 and the cage of 6 cells totalling 39 must be made of 456789. That then limits the two squares A6 & A7 to 4, 5 and 6.

Got all that very quickly.  Getting from there to the reductions in your first screenshot has be stumped.  Still working through the available combinations.

Title: Re: Sudoku
Post by: Wowbagger on 16 June, 2020, 10:29:07 am

Can you post a screenshot of where you are up to? I can't recall my thought processes.

I've reopened the puzzle and loaded it as far as the "Sudoku Solver" takes you before it runs out of ideas.

Title: Re: Sudoku
Post by: SoreTween on 16 June, 2020, 01:02:26 pm

One step forward, 5&6 placed in B4, B5 & A7.

(http://soretween.altervista.org/misc/Sudoku/sod753-1.jpg)

I've not fully investigated the implications of that step yet.  Not having much time at the moment but that seems to help.  I keep seeing things in the first couple of minutes I'd not spotted in earlier long sessions (I have 3 on the go at the moment)

[ETA]Ah yes, the 4 within the 39 group has been pushed inside square 2, that's the next step.  Investigating....

Title: Re: Sudoku
Post by: Wowbagger on 16 June, 2020, 01:44:36 pm

(click to show/hide)

That means that the 3 squares A4, A5 and C6 must share 1, 2 & 3. A4 & A5 must add up to 5, therefore C6 must be 1.

Also, the cage valued at 33, starting in C8, must contain 7, 8 & 9. Therefore F8 cannot be 7.

Title: Re: Sudoku
Post by: SoreTween on 16 June, 2020, 03:46:35 pm

(click to show/hide)

Quote from: Wowbagger on 16 June, 2020, 01:44:36 pm

That means that the 3 squares A4, A5 and C6 must share 1, 2 & 3. A4 & A5 must add up to 5, therefore C6 must be 1.

Yep, that follows on from pushing the 4 in the 39 inside box 2.  2&3 and 1&4 are complimentary pairs in A4 & A5 (totalling 5 as you say).  Remove the 4 also removes the 1 leaving C6 the only square in box 2 that can be 1.

Quote from: Wowbagger on 16 June, 2020, 01:44:36 pm

Also, the cage valued at 33, starting in C8, must contain 7, 8 & 9. Therefore F8 cannot be 7.

D'oh!  That 33 is one of the early gifts.  Pure inattention there.  I accidentaly closed the tab, prior to that I had those cells shown as '789 3645' but the cookie doesn't save that detail.

Title: Re: Sudoku
Post by: Wowbagger on 16 June, 2020, 04:00:18 pm

You can also make progress with the innies/outies in Column 7.

That, in turn, has implications for the 3 cells total value 15 in the bottom RH block , and of course the bottom row of the RH middle block..

Title: Re: Sudoku
Post by: Wowbagger on 18 July, 2020, 11:08:17 pm

https://www.killersudokuonline.com/play.html?puzzle=D37shr35313&year=2020

That was an utter sod.

Normally, even for supposedly "hard" puzzles, a point comes when it just falls into place. That didn't for me. I was battering it for a couple of hours, I reckon.

Title: Re: Sudoku
Post by: Pickled Onion on 19 July, 2020, 01:47:28 pm

Yesterday's Guardian killer (https://www.theguardian.com/lifeandstyle/2020/jul/18/killer-sudoku-719) has overlapping inner shapes. Is that a thing, or a mistake? I failed at the point where I got to filling in that area, and can't be arsed to backtrack as I can't see that I went wrong anywhere.

Title: Re: Sudoku
Post by: Wowbagger on 19 July, 2020, 02:26:29 pm

A quick count-up gave a grand total of 405 (9*45), so I think that must have been a mistake. Otherwise, that extra square would have been counted twice and the total would have ben >405.

Title: Re: Sudoku
Post by: Wowbagger on 18 December, 2020, 03:22:04 pm

https://www.killersudokuonline.com/play.html?puzzle=D3sk7v25465&year=2020

Moderate, allegedly. Took me ages. Very hard to unpick, right to the end.

Title: Re: Sudoku
Post by: JennyB on 28 December, 2020, 05:45:18 pm

I'm addicted to Simon Anthony's solves on Cracking the Cryptic; elegant handcrafted Sudoku variants and other puzzles solved in  real time with a running commentary of his reasoning.

Here's one that I'm particularly proud of having worked out for myself - eventually: The Miracle Sudoku (https://www.youtube.com/watch?v=yKf9aUIxdb4&t=8s)

Title: Re: Sudoku
Post by: Wowbagger on 28 December, 2020, 07:48:51 pm

Very good!

I solved it eventually, after some errors and backtracking. I've sent it to a maths teacher (retired) pal to see how he gets on. This sort of thing is right up his (and his wife's) street. Both very good mathematicians.

Title: Re: Sudoku
Post by: rogerzilla on 28 December, 2020, 09:59:14 pm

A recent Top Tip to "Viz" was along the lines of "Fill them with whatever numbers you like.  I've noticed that no-one ever checks your answers".

Title: Re: Sudoku
Post by: Wowbagger on 26 April, 2021, 07:20:38 pm

https://www.killersudokuonline.com/play.html?puzzle=D36l3s85595&year=2021

I get fed up with these Monday puzzles which claim to be easy and then take me ages. If they are genuinely easy I solve them in my head. That one's a git in my view - unless I'm missing something fundamental.

Title: Re: Sudoku
Post by: Wowbagger on 07 June, 2021, 01:11:36 pm

https://www.killersudokuonline.com/iphone/player.html?puzzle=D2jnnja5636&year=2021

Yesterday’s was very satisfying and elegant, I thought.  Labelled as “extreme” but I didn’t find it as hard as the usual Sunday puzzles.

Title: Re: Sudoku
Post by: Wowbagger on 25 March, 2022, 07:40:48 am

https://www.killersudokuonline.com/iphone/player.html?puzzle=D35a0tq5927&year=2022

This is marked as “Moderate” but I am finding it a right hit. The hardest I’ve had for ages on this site.

Title: Re: Sudoku
Post by: Bilbo44 on 21 June, 2022, 09:08:10 am

Yep I am playing sudoku almost 10 years especially when I'm bored or I'm on the road to somewhere :)
I became a big fan of this game I even started to read sudoku blogs (link removed) maybe I'm a bit obsessed of sudoku haha

Title: Re: Sudoku
Post by: Wowbagger on 20 June, 2023, 11:24:52 am

Quote from: Wowbagger on 25 March, 2022, 07:40:48 am

https://www.killersudokuonline.com/iphone/player.html?puzzle=D35a0tq5927&year=2022

This is marked as “Moderate” but I am finding it a right hit. The hardest I’ve had for ages on this site.

Clicking on that link today leads to “Account suspended”. The webmaster clearly needs to put another $ in the meter.

What am I going to do today?

Title: Re: Sudoku
Post by: SoreTween on 21 June, 2023, 02:12:10 pm

Quote from: Wowbagger on 20 June, 2023, 11:24:52 am

Clicking on that link today leads to “Account suspended”. The webmaster clearly needs to put another $ in the meter.

What am I going to do today?

Coins have been deposited.