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.

All 253 Patterns from Christopher Alexander's a Pattern Language – Summarized

https://claytondorge.com/patterns-list
1•toomuchtodo•1m ago•1 comments

The Powerhouse of the AI Chip

https://twitter.com/joefioti/status/2077430481809989662
1•gmays•4m ago•0 comments

NotchAgent – native macOS notch control for AI agents running under herdr

https://github.com/ykushch/agsig
1•ykushch•6m ago•0 comments

The 1.5°C Lie: The Math That Climate Models Are Hiding from You

https://comuniq.xyz/post?t=1426
1•01-_-•8m ago•0 comments

Men That Don't Fit In

https://www.poetryfoundation.org/poems/58012/the-men-that-dont-fit-in
1•oidar•9m ago•1 comments

Turn the Lights on Before the Factory Starts

https://nextwaveoftech.com/posts/turn-the-lights-on-before-the-factory-starts
1•jameslaneyno9•9m ago•0 comments

AI is changing the way consumers shop, and businesses need to get ready

https://www.rnz.co.nz/news/business/773456/ai-is-changing-the-way-consumers-shop-and-businesses-n...
3•billybuckwheat•12m ago•1 comments

Ask HN: Why can't Google create monopolies anymore?

2•BeForce•16m ago•1 comments

Software Skill Space

https://vis.csh.ac.at/software-skill-space/
1•gmays•17m ago•0 comments

DNS Bypass Tweets Keep Uptobox Employee's €197K Frozen in Disney Piracy Case

https://torrentfreak.com/dns-bypass-tweets-keep-uptobox-employees-e197k-frozen-in-disney-piracy-c...
1•gslin•18m ago•0 comments

Show HN: Stream Android Emulators to a Browser Window

https://github.com/hsandhu/serve-avd
2•rsandhu•19m ago•0 comments

Show HN: NextBest – See what skincare people recommend

https://www.nextbest.one
1•kalila855•19m ago•0 comments

Build a website for AI pics for dating apps in 20 hours, launched ads, failed

1•MaximTsyg•20m ago•1 comments

Who Uses ChatGPT Matters

https://www.marginpoints.com/issues/2026-07-21-openai-s-advertising-audience
1•historian1066•21m ago•0 comments

Just Say the Word

https://newsroom.spotify.com/2026-07-14/talk-to-spotify-announcement-beta/
1•yruzin•21m ago•0 comments

Most of your Hacker News karma comes from comment scores only you can see

https://blog.nathanlangley.dev/posts/hn-hidden-score.html
1•ninjahawk1•22m ago•1 comments

Boox Go 10.3 (gen II) Lumi: First impressions

https://manualdousuario.net/en/boox-go-10-3-lumi-first-impressions/
5•rpgbr•24m ago•0 comments

Why not just publish the votes?

https://sweatofthebrow.blogspot.com/2026/07/why-not-just-publish-votes.html
5•whall6•25m ago•1 comments

Alphabet hikes 2026 capex spend to $195B-$205B

https://www.cnbc.com/2026/07/22/google-earnings-q2-goog-live-updates.html
2•mfiguiere•29m ago•1 comments

Cursor, Codex, Gemini CLI, Antigravity hit by sandbox escapes

https://www.bleepingcomputer.com/news/security/cursor-codex-gemini-cli-antigravity-hit-by-sandbox...
2•PhilippGille•30m ago•0 comments

Capra, Cribl's Design System

https://cribl.io/blog/introducing-capra-cribls-design-system/
2•ilreb•30m ago•0 comments

Star Axis

https://en.wikipedia.org/wiki/Star_Axis
2•Thevet•33m ago•0 comments

Malleable Computing, Emacs, and You

http://yummymelon.com/devnull/malleable-computing-emacs-and-you.html
21•kickingvegas•34m ago•0 comments

Show HN: What's one random memory from your childhood that you'll never forget?

https://mil.now
2•untitled-now•36m ago•0 comments

OAuth DPoP

https://fusionauth.io/docs/lifecycle/authenticate-users/oauth/dpop
2•mooreds•37m ago•0 comments

SIMD for Collision

https://box2d.org/posts/2026/07/simd-for-collision/
2•birdculture•39m ago•0 comments

Q2 2026 earnings call: Remarks from Alphabet CEO

https://blog.google/company-news/inside-google/message-ceo/alphabet-earnings-q2-2026/
4•ilreb•40m ago•1 comments

OpenAI Model Hacks into HuggingFace During Cybersecurity Evaluation

https://thezvi.substack.com/p/openai-model-hacks-into-huggingface
3•nedruod•40m ago•0 comments

Show HN: I brute-forced a wooden Antikythera-style puzzle in Rust

https://github.com/garyhtou/grecian-computer
2•garyhtou•42m ago•0 comments

Drawn Apart: Remote GPU Fingerprinting

https://orenlab.cis.bgu.ac.il/p/DrawnApart-TOPS
2•matt_d•42m ago•0 comments