[HN Gopher] Show HN: Jumping Julia Maze
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       Show HN: Jumping Julia Maze
        
       This is inspired by Julia Robinson Mathematics Festival.
       https://jrmf.org/
        
       Author : thathoo
       Score  : 26 points
       Date   : 2024-11-25 07:14 UTC (2 days ago)
        
 (HTM) web link (jumpingjuliamaze.onrender.com)
 (TXT) w3m dump (jumpingjuliamaze.onrender.com)
        
       | monkeydust wrote:
       | This is great. Simple to get, not too simple to solve. One I will
       | share with my kids, plus now introduced to Julia Robinson
       | festival. Thanks for sharing.
        
       | kjrfghslkdjfl wrote:
       | Better challenge: generate these puzzles in a way to have a
       | unique solution.
        
         | 420official wrote:
         | I highly doubt it's possible to have a single solution in a
         | puzzle like this at any size
        
           | Atiscant wrote:
           | At least it is possible to force a single solution
           | (discounting backtraces which is always possible) in 4x4:
           | | 2 | 3 | 3 | 3 |        | 3 | 3 | 3 | 3 |        | 3 | 3 | 3
           | | 1 |        | 3 | 3 | 3 | G |
           | 
           | I'm fairly sure the only solution here is 2 down to 3 right
           | to 1 to goal. You can of course then use this to generate a
           | couple of more by changing all the numbers that are
           | impossible to reach.
        
         | Atiscant wrote:
         | Or for the mathematically inclined: How many n x n puzzles with
         | unique solutions exists for a given size n?
         | 
         | n=1 is trivial, and n=2 it small enough to enumerate with 3^4 =
         | 81 solutions, but many of them being degenerate (no solutions),
         | but already n=3 is pretty bad with ~20.000 possible puzzles. I
         | do not see an obvious path to compose solutions either and make
         | use of some kind of structural induction.
        
       | wingmanjd wrote:
       | Are these always solvable? The handful of 4x4's I've had don't
       | seem to be.
        
         | Atiscant wrote:
         | With arbitrary generation rules they are surely not. This is a
         | counter example on 4x4:                 | 1 | 1 | 1 | 1 |
         | | 1 | 3 | 3 | 3 |       | 1 | 3 | 2 | 2 |        | 1 | 3 | 2 |
         | G |
         | 
         | Or                 | 2 | 2 | 2 | 2 |       | 2 | 2 | 2 | 1 |
         | | 2 | 2 | 2 | 2 |        | 2 | 1 | 2 | G |
         | 
         | This seems to be able to be understood as a reachability graph
         | problem of some sort perhaps.
         | 
         | Edit: formatting
        
         | CrazyStat wrote:
         | I did about 10 4x4s and 6x6s and they were all solvable.
        
         | jumpoddly wrote:
         | Worth noting, since it was absent in the rules, that it is
         | unnecessary to touch all of the squares.
        
       | pierrebai wrote:
       | Knowing that a typical maze will have branching paths at the
       | beginning, but necessarily one good path at the end, I find it
       | easier to start from the goal and work my way backward.
        
       | phkahler wrote:
       | The wording isn't good. The number does not indicate how many
       | jumps you need to make. It indicates how far you need to jump.
       | 
       | Otherwise fun!
        
       | khebbie wrote:
       | It seems to make a server request when Generating a new maze.
       | Making the maze working fully Client side should be doable..
        
       | panki27 wrote:
       | Seems like I'm too late and it got hugged to death? Page is not
       | loading for me.
        
       | pierrec wrote:
       | I love the concept, but I found it a bit disappointing that
       | larger puzzles are not really more difficult (they seem to have a
       | lot of solutions). Just in case anyone else wants more of a
       | challenge... I hand-wrote a 10x10 that should be harder to crack:
       | 1  2  1  2  2  3  1  1  2  2         3  2  3  3  3  3  3  3  3  3
       | 3  3  3  3  3  3  3  3  3  3         2  1  2  2  3  2  1  1  3  1
       | 2  1  3  3  1  3  3  1  3  1         3  3  1  3  3  3  3  3  3  3
       | 2  3  2  2  2  2  1  2  2  3         3  3  3  3  1  3  3  1  3  2
       | 1  3  2  3  3  3  3  3  3  3         2  1  3  3  2  2  2  2  1  F
       | 
       | Unless I made a mistake, the simplest solution is not easy to
       | find. Obviously I was thinking about an algorithm to create
       | harder "Jumping Julia" puzzles. Definitely doable but I think
       | I'll leave it at that!
        
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       (page generated 2024-11-27 23:01 UTC)