anderson's Puzzle Blog

Puzzle 19: Looking for the Loop

with 5 comments

Instructions (taken from the WPC): Draw a single closed loop in the grid by connecting horizontally and vertically neighboring cells. The loop can touch itself, but it cannot cross or overlap itself. Cells with numbers cannot be parts of the loop. Each number in the grid indicates how many of the eight neighboring cells are used by the loop.

Also, in this puzzle, the loop cannot go through any squares with an X (yeah, I know it’s sort of inelegant; looking for the loop is quite a bit more difficult than tapa-like loop when it comes to uniqueness).

Notes: I am currently attempting to stick to a one puzzle per week schedule. Let’s see whether I keep my promise next Monday/Sunday!


Written by qzqxq

October 15, 2012 at 9:36 pm

Posted in Misc. Loop, Puzzles!

Tagged with ,

5 Responses

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  1. Having trouble with this one. As posted, I think there are no solutions due to the top left. The 2 seals the top edge off, the 5 forces you to enter it through both R3C1 and R3C3, and then there are too many loop segments that have to be drawn for the 2 and 5 to both be satisfied.

    By assuming the left 8 was a 7, things seem to be mostly fixed, with the whole bottom and right getting forced. But the top left still has a few solutions (5?), particularly with how the loop has the option of jutting out to R1C1 or not. I cannot figure out how to get rid of this with the clue layout and general loop structure you have here.


    October 16, 2012 at 2:40 am

    • I don’t think you need to enter through both R3C1 and R3C3; you could have the path go R3C4->R3C3->R4C3 and it would still work out.


      October 16, 2012 at 5:30 am

      • Oops, you’re right. Much more used to the no-touch version of these rules and accidentally lapsed into them when thinking about that area…


        October 16, 2012 at 1:52 pm

  2. It is easier satisfying uniqueness with this generalized version than my version of having all clues equaling 4( i think its really hard to make one without ‘X’s when all clues are 4,but possible).You can even work easily with a version that has both usual and inverted clues without using ‘X’s.

    Anuraag Sahay

    October 17, 2012 at 7:40 am

  3. […] 8. Looking for the Loop […]

    MACR 2012 Puzzles |

    December 7, 2012 at 11:12 pm

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