Sunday 20 September 2009

Friday Puzzles #14

So this week’s (last week’s?) puzzle was slightly delayed as I was concentrating on the nikoli sudoku time trial. My laptop was to have other ideas: deciding to delete/corrupt/mutilate/whatever a crucial windows system folder – and so I had to rush to a computer room to take part. Being all of a fluster, and starting a full minute late I managed a meagre 6th. Having gone back later, I improved upon my time by nearly two minutes. C’est la vie.

The upshot of all that is that I wanted to write my own fairly challenging sudoku – but I find writing Sudoku puzzles (or at least good ones) to be a lot more challenging than other nikoli puzzle types. So, cutting my losses for now, I’ve instead tried my hand at Heyawake. You can find the rules to the puzzle here.

I probably ought to have introduced the puzzle to my blog with a nice gentle introduction – but instead I’ve gone with a sink-or-swim puzzle where you’ll have to do a bit of thinking about the rules and their implications.
    #019 Heyawake – rated medium
All puzzles © Tom Collyer 2009


  1. Hey, I just wanted to thank you for these puzzles. I’ve been doing them intermittently and they’re a fun distraction.

    This week’s I think is ambiguous, unless I’ve done it wrong (entirely plausible). Here’s my solution up until you start to get choices: (spoilers).

  2. What you have done is right so far – you’ve got the basics worked out fine it seems. The two gaps towards the bottom right can be filled in straight away.

    To finish off the puzzle you need to think hard about the middle-left room labelled 3 – and in particular how it interacts firstly with Row 5 and then subsequently with Column 4 – remembering that you can’t have empty space through 3 consecutive rooms.

    In all fairness it took me a couple of minutes to see that again, and I’ve been doing these for a while now – I might have to regrade this as hard.

    Thanks for your interest!

  3. On further inspection, you do appear to be right. I was almost sure that there were two valid ways of filling in the room labelled 3, but rather foolishly I only checked one of them – trying to work through the other way now, it of course doesn’t work.

    Lesson learnt: if you think the problem is wrong, it’s probably not.


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