Friday 3 May 2013

Friday Puzzles #207

I'm fairly sure, Dearest Reader, that you won't have seen many yajilin puzzles like this before.  Enjoy!

EDIT: Original posted puzzle had multiple solutions; please see the comments below for the discussion.  First "correction" had a counting error!
    #244 Yajilin – rated medium
All puzzles © Tom Collyer 2009-13.

9 comments:

  1. Very pretty. I like the way some of the 3x3 boxes work. However, either I am tired out of my mind and missing something, or this one seems to have two independent problems leading to multiple solutions: The small problem lies in the 3x3 box just above the central X. This seems easy enough to fix. On the top left corner however, one seems to be able to split the required cells into connectors (for the two existing near-loops at that point) of arbitrary length. This one will probably require extensive rerouting.

    ReplyDelete
    Replies
    1. I didn't spot anything wrong with the puzzle, besides the use of a uniqueness argument in said 3x3 box.

      Delete
    2. I test solved this once on paper and then once in paint before posting and didn't notice anything like this. Perhaps I was overlooking the same thing each time.

      Anyway, here is the (intended) solution: http://3.bp.blogspot.com/-2LYOX68eNmU/UYT4RldvaoI/AAAAAAAAAyE/SLzaIYpZyD8/s1600/244ya_sol.png

      The 3x3 box you mention is resolved by the 4 down clue in the top row. As for the top left - I'm not sure what you mean. This came right at the end of my solve, and is set up by the 2 up clue in the 3rd row from bottom...

      Delete
  2. http://i3.photobucket.com/albums/y62/Termital/dr244.png contains my progress before possibilities explode. This error is probably on my part, but I have gone over it a few times and I can't for the life of me spot where I went wrong.
    Your solution also seems perfectly fine, which makes me wonder why I was certain of certain choices earlier in the puzzle which now look like they should have been at least ambiguous.

    ReplyDelete
    Replies
    1. Thanks for sharing! I spent a lot of time analysing how and where the ambiguities came up, and interestingly they were all intimately related. I suspect the branch in my thinking came with incorrectly thinking there was only one way to resolve the left blank 3x3 area. Our two images clearly demonstrate this isn't the case.

      Thankfully it's an easy fix. Changing R8c10 from a "2 right" clue to a "2 down" clue fixes things.

      Delete
    2. Also, do you mind me asking for your name so I can add you blog to my links?

      Delete
    3. Thanks. Antonis Lalatsas is my actual name. And thanks to your analysis I know know what options I missed during solving.

      Delete
    4. Hey Tom. Did you mean to change the 2 down clue to a 3 down clue? Maybe you forgot to count the black square directly under the 2?

      Delete

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