Killer Sudoku Contest 13/02/21

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Feadoor
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Joined: Thu 17 May, 2018 7:08 am

Killer Sudoku Contest 13/02/21

Post by Feadoor » Mon 08 Feb, 2021 7:55 am

If anyone's looking for something to do this Saturday afternoon, here's a Sudoku contest that isn't quite your usual fare.

https://logic-masters.de/Wettbewerbe/CE ... php?id=159

In a nutshell, 27 themed Killer Sudoku, fixed starting time, first to finish them all wins. I tested the puzzles (and wrote one of them) and can recommend the contest if you have the time (or even if you don't!)

detuned
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Re: Killer Sudoku Contest 13/02/21

Post by detuned » Sun 14 Feb, 2021 11:35 am

As this contest is very much in the “just for fun” category with an open-ended finish date, I don’t think I’m doing too much harm by sharing a few thoughts now.

I battled my way through this this yesterday. A cursory glance at the results table tells you a couple of things:

https://logic-masters.de/Wettbewerbe/CE ... php?id=159

Firstly that Kota Morinishi is a phenomenal genius. And second that this is brutally hard. For UK context, the hardest “deadly” ratings you find for killer sudoku in the Times newspaper are child’s play compared to these puzzles. I think Sam is being far too optimistic when he suggests you might finish this in an afternoon - in all honesty you’ll need to clear out a day to do this at minimum. Getting through all of these at all in any length of time and in any number of sittings is in itself a remarkable achievement. Incidentally, I’d fully recommend keeping these results open and then refreshing the page as you go along, since it will confirm whether your answer entry was correct.

The other thing I’d have to say is that the theme of the contest is mind blowing. 27 puzzles where all the cages have the same single total, and with no uncaged given digits, is on another level. I once made a puzzle with all 20/cages and 3 uncaged givens, and it took forever to get that coming out uniquely. If I were nit-picking slightly then I might say that our creators have sometimes veered over into the computer-assisted line whilst setting these - I don’t think anyone sets anything like this entirely by hand - but all in all this is easily the most remarkable set of killer sudoku in existence that I’m aware of. If you had to push me, I’d say the 27 puzzle is probably the most brilliant construction, given that its 15 cages entirely cover the 81 cells of the grid. I don’t think I’d have even dared to consider whether something like that was even possible.

I’ll finish by describing my own experience. By the end I was cycling through my print-outs staring at each puzzle in turn for a bit trying to see what several hours of staring hadn’t already seen up to that point! I think I could have had a significantly faster run at these by being more shall we say, pragmatic, about some well-chosen bifurcations - but at that point I thought the whole thing would be more satisfying if I could work everything out without having to do that. I am glad to say that in the end I did manage it. (Although speaking the day after, it’s also fair to say I’m also truly knackered!)

Feadoor
Posts: 219
Joined: Thu 17 May, 2018 7:08 am

Re: Killer Sudoku Contest 13/02/21

Post by Feadoor » Sun 14 Feb, 2021 2:56 pm

detuned wrote:
Sun 14 Feb, 2021 11:35 am
If I were nit-picking slightly then I might say that our creators have sometimes veered over into the computer-assisted line whilst setting these - I don’t think anyone sets anything like this entirely by hand - but all in all this is easily the most remarkable set of killer sudoku in existence that I’m aware of.
Absolutely accurate when it comes to my puzzle - 7 cages placed by hand and a heavily computer-assisted finish - but clover set all 23 of her puzzles by hand (with many many failed attempts) which I find absolutely astonishing! I was able to watch some of the setting take place live and what she can do with killer cages is magical.

detuned
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Re: Killer Sudoku Contest 13/02/21

Post by detuned » Sun 14 Feb, 2021 3:09 pm

If that's the case then I'll take by back my nit-picking and doff my hat. That is extraordinary!

It's not to say setting using computer assistance is somehow a bad thing by the way - if we took that out of the equation we'd lose many, many fine puzzles. If that 27 puzzle was set by hand I will also eat my doffed hat! Perhaps mine was a reaction to being pulverised by so many subtle deductions that I didn't really catch on for a long while or realise where I should be looking.

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