Show HN: Jumping Julia Maze

(jumpingjuliamaze.onrender.com)

23 points | by thathoo 3 days ago ago

13 comments

  • phkahler 3 hours ago

    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!

  • panki27 an hour ago

    Seems like I'm too late and it got hugged to death? Page is not loading for me.

  • khebbie 2 hours ago

    It seems to make a server request when Generating a new maze. Making the maze working fully Client side should be doable..

  • pierrebai 4 hours ago

    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.

  • monkeydust 5 hours ago

    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.

  • wingmanjd 4 hours ago

    Are these always solvable? The handful of 4x4's I've had don't seem to be.

    • Atiscant 4 hours ago

      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 4 hours ago

      I did about 10 4x4s and 6x6s and they were all solvable.

    • jumpoddly 4 hours ago

      Worth noting, since it was absent in the rules, that it is unnecessary to touch all of the squares.

  • kjrfghslkdjfl 5 hours ago

    Better challenge: generate these puzzles in a way to have a unique solution.

    • Atiscant an hour ago

      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.

    • 420official 2 hours ago

      I highly doubt it's possible to have a single solution in a puzzle like this at any size

      • Atiscant an hour ago

        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.