frontpage.
newsnewestaskshowjobs

Open Source @Github

fp.

Open in hackernews

Generating Mazes with Inductive Graphs (2017)

https://jelv.is/blog/Generating-Mazes-with-Inductive-Graphs/
20•todsacerdoti•1y ago

Comments

tomfly•1y ago
where is the entrance and exit?
Jaxan•1y ago
Doesn’t matter, because all positions are reachable. So just pick any two positions at the border and remove a wall.
kazinator•1y ago
Here is a maze that was generated recursively starting at the upper left cell.

  +    +----+----+----+----+----+----+----+----+----+
  |    |                        |                   |
  |    |                        |                   |
  +    +----+----+    +----+    +----+    +----+    +
  |              |         |                   |    |
  |              |         |                   |    |
  +----+----+    +    +----+----+----+----+----+    +
  |              |    |                        |    |
  |              |    |                        |    |
  +    +----+----+    +    +----+----+----+    +    +
  |         |              |              |    |    |
  |         |              |              |    |    |
  +    +----+    +    +----+----+----+    +    +----+
  |              |    |                   |    |    |
  |              |    |                   |    |    |
  +----+----+----+    +    +----+----+----+    +    +
  |                        |                   |    |
  |                        |                   |    |
  +    +----+----+----+    +    +----+----+----+    +
  |    |    |              |    |              |    |
  |    |    |              |    |              |    |
  +    +    +    +    +----+    +    +----+    +    +
  |    |    |    |    |         |    |         |    |
  |    |    |    |    |         |    |         |    |
  +    +    +    +    +----+----+----+    +    +    +
  |    |    |    |    |                   |         |
  |    |    |    |    |                   |         |
  +    +    +----+    +    +----+----+    +----+----+
  |              |         |                        |
  |              |         |                        |
  +----+----+----+----+----+----+----+----+----+    +

It matters to start there because it will be easier if you go backwards.

The maze has 100 cells. For each cell, we can calculate which exit goes back toward the entrance, assigning the letters U, D, L, R:

  U R R D L L R D L L
  U L L D L U L L L U
  R R U D D L L L L U
  U L D L L R R D U U
  U L L U D L L L U D
  R R R U L R R R U D
  U D R R U U R R D D
  U D U U R U U D L D
  U D U U D L L L U L
  U L L U L R R U L L
Stats:

  L - 33
  U - 29
  R - 20
  D - 18
Left and Up are more frequent back-to-entrance escapes than Right or Down. This is because of the way the maze was generated.

To check the hypothesis, we should analyze it in the other direction. For each cell, determine the exit which heads in the direction of the exit:

  D R R D L L R D L L
  D R D D L U L L L U
  D L L D D L L L L U
  D L R D L R R D D U
  R R U D D L L L U D
  R R R R D R R R U D
  U D R D L U R R D D
  U D U D R U U D L D
  U D U D R R R D U L
  U L L R U R R R R D
Stats:

  D - 30
  R - 28
  L - 24
  U - 18
There is a weaker bias for the D-R axis toward the exit, compared to the L-U axis toward the entrance. I suspect if we study larger numbers of larger mazes, we will find similar findings.

So that is to say, it is easier to navigate the maze in the reverse direction: the heuristic to try left/up exits will work more often than the right/down in the proper direction.

smartmic•1y ago
From the book "Mazes for Programmers" by Jamis Buck, 2015, The Pragmatic Programmers (a must-read for any maze/programming enthusiast!):

> Aren't mazes supposed to have starting points and end points? […] honestly, […] it's entirely up to you. […] The maze […] is a perfect maze, and one of the attributes of a perfect maze is that there exists exactly one path between any two cells in it. […] You pick them, and there's guaranteed to be a path between them.

You do not need to choose an entrance or exit only on the sides, but you can also choose "Pacman-style" where the goal is to reach points inside the maze.

"Perfect" refers to the mathematical/logical properties of a maze (i.e. no loops), not the aesthetical aspect. I have not checked though if the mazes in the source here are all perfect.

kazinator•1y ago
While you can put the entrance and exit wherever you want, if you know that the maze was generated by a recursive branching process which had a starting point somewhere, it probably behooves you to put the start at that point corresponding to the root of the tree, so that the maze wanderer faces the most branching choices.

Laying out the abstract maze tree into the rectilinear grid of cells obfuscates the tree somewhat, but not entirely. A process that generates from upper left to lower right, for instance, will tend to generate cells whose parent-headed exits going left and up more often than not, making the reverse direction a bit easier.

(Again, it depends on the maze generation process.)

kazinator•1y ago
Making random mazes in a rectilinear grid is a good exercise for one big reason: mazes are not all the same. Mazes have style can be very knotty and twisty, or have long passages. You can add hacks into a given algorithm to vary the style, but there are certain things it won't necessarily do.

Show HN: Agent2Creator – a video social network whose members are AI agents

https://agent2creator.vidmoat.com
2•abilafredkb•10m ago•0 comments

Drones with Claws

https://spectrum.ieee.org/arctic-iceberg-drones
1•asdefghyk•13m ago•1 comments

The Art and Beauty of Blade Runner

https://nappertime.com/the-art-of-and-beauty-of-blade-runner/
1•cocacola1•15m ago•0 comments

Verbatim: What Is a Photocopier?

https://www.nytimes.com/video/opinion/100000002847155/verbatim-what-is-a-photocopier.html
1•grubbs•15m ago•0 comments

Toward safe, flexible, and efficient software in Common Lisp [video]

https://www.youtube.com/watch?v=of92m4XNgrM
1•so-cal-schemer•16m ago•1 comments

The Risks of Artificial Intelligence: What Users Need to Understand Befor

https://moztako.me/hidden-risks-of-artificial-intelligence/
1•vadinho•20m ago•0 comments

Show HN: Nice Licence – An anti-copyleft permissive licence

https://github.com/Jamedjo/git-hunk/commit/240ac0f7e986fbe783a7de1c220fc047771ee059
1•jamedjo•23m ago•0 comments

Show HN: Active Source of Truth for Your Coding Agents

https://meetless.ai
1•anphamthanh•27m ago•1 comments

Are you aware of the popularity poll for official Japanese characters?

1•GanJin•28m ago•0 comments

Hannelore Schmatz

https://en.wikipedia.org/wiki/Hannelore_Schmatz
1•doener•29m ago•0 comments

Active Inference as Context Acquisition for AI Agents

https://arxiv.org/abs/2608.19202
1•Anon84•30m ago•0 comments

Adapting Fossil-scm as a platform for AI agentic workflow

https://github.com/BenSiv/fossil-scm
1•thunderbong•34m ago•0 comments

Gspot: Gcloud auth monitoring for long-running coding agents

https://github.com/Somnora/GSPOT
1•Somnora•42m ago•0 comments

Show HN: A comic and manga viewer component for React

https://react-comic-viewer.kkweb.io
2•piro0919•42m ago•0 comments

NanoGPT Speedrun

https://github.com/KellerJordan/modded-nanogpt
2•kelseyfrog•45m ago•0 comments

Lower air pollution leads to increased warming

https://twitter.com/Electroversenet/status/2090891691649560717
1•delichon•48m ago•0 comments

Most Popular Programming Languages: Data from 1958 to 2025

https://www.youtube.com/watch?v=ZTPrbAKmcdo
1•so-cal-schemer•49m ago•1 comments

Software Engineering in the Agentic Era

https://simonwillison.net/2026/Feb/23/agentic-engineering-patterns/
2•silverpiranha•50m ago•0 comments

US Military newspaper editor voices censorship fears after being fired

https://www.bbc.com/news/articles/cm2g23ng8p4o
6•tartoran•51m ago•0 comments

Mathematicians will probably become obsolete before anyone else [pdf]

https://olli.unt.edu/handouts/fall24/tk-writing-sample.pdf
2•tiahura•56m ago•0 comments

Show HN: Lens AI – generate your JSON-LD files and keep them up-to-date

https://knowledgelens.ai/
1•k7vin•1h ago•0 comments

A heart surgeon's confession: it was never the cholesterol

https://twitter.com/robertlufkinmd/status/2091265696076624301
2•bilsbie•1h ago•0 comments

Enabling the next-generation trait solver on nightly

https://blog.rust-lang.org/2026/08/21/enabling-next-solver-on-nightly/
1•lbw1215•1h ago•0 comments

You don't have to make money with AI. You could just be happier

https://hibernation.dev/posts/ai-for-happiness-not-money/
2•ositowang•1h ago•0 comments

Automakers Keep Adding Screens, but Buyers Want Something Else

https://www.autoblog.com/news/automakers-keep-adding-screens-but-buyers-want-something-else
2•delichon•1h ago•0 comments

Hacker News RSS

https://hnrss.github.io/
2•sillysaurusx•1h ago•0 comments

Don't ask me my f*#&ing name

https://runninganddancing.substack.com/p/dont-ask-me-my-f-and-ing-name
4•HakuGulati•1h ago•2 comments

A look at CrossPoint e-reader firmware

https://lwn.net/Articles/1087635/
3•pykello•1h ago•0 comments

Parallel worktrees running all services on local branch domains

https://github.com/jdtzmn/port
1•amadeuspagel•1h ago•0 comments

Kinds of Luck

https://pmarchive.com/luck_and_the_entrepreneur.html
1•AnhTho_FR•1h ago•0 comments