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.

Mike Williams and Björn Gustafsson on Building the Jam (Erlang) [video]

https://www.youtube.com/watch?v=sRTierdN9c4
1•sbuttgereit•1m ago•0 comments

Show HN: Strophae, multi personas chat interface

https://mtct.github.io/strophae/
1•mtct88•2m ago•0 comments

Ask HN: What are you using local LLMs for?

1•adam_patarino•2m ago•0 comments

Sample More, Reflect Less: Self-Refine and Reflexion Lose to Repeated Sampling

https://arxiv.org/abs/2607.28576
1•sbulaev•3m ago•0 comments

Math shows why your vote may not count the way you think it does

https://phys.org/news/2026-07-math-vote.html
1•pseudolus•4m ago•0 comments

A Culture That Could Only Count

https://robertxworld.com/the-culture-that-could-only-count/
1•devrob•8m ago•0 comments

Digital Independence Day: Switch to the good side every first Sunday

https://diday.org/en/
1•whilenot-dev•8m ago•0 comments

Why is assisted dying so rare, even where it's legal?

https://preservinghope.substack.com/p/why-is-assisted-dying-so-rare-even
1•arielzj•9m ago•1 comments

What a Hedge Fund's Implosion Says About the A.I. Trade

https://www.nytimes.com/2026/07/31/business/dealbook/situational-awareness-ai-hedge-fund.html
3•donohoe•9m ago•0 comments

Farmers spreading crushed glass on their crops

https://www.abc.net.au/news/2026-07-31/ground-glass-silicon-fertiliser-farm-productivity/106963488
1•porjo•9m ago•0 comments

How the Words We Teach English Language Learners Changed

https://pudding.cool/2026/07/essential-words/
1•surprisetalk•9m ago•0 comments

Amiga Pips the PC for Mission-Critical Computing at NASA (2021)

https://hackaday.com/2021/08/16/retrotechtacular-amiga-pips-the-pc-for-mission-critical-computing...
1•Bluestein•10m ago•0 comments

Shipping code without human verification

https://thenewstack.io/ship-code-without-verification/
1•tonkkatonka•11m ago•1 comments

Hello from Zernote

https://blog.zernote.com/hello-from-zernote/
1•sagotly•11m ago•0 comments

Ufc noche free: legal ways to watch and verify the card

https://mxltv.net/mx
1•cynthial485•15m ago•0 comments

How to Stop Procrastinating

https://www.nytimes.com/2026/07/31/well/stop-procrastinating-tips.html
1•EndXA•16m ago•0 comments

Violin Plot

https://en.wikipedia.org/wiki/Violin_plot
1•tosh•17m ago•0 comments

The End of an Era

https://hughhowey.com/the-end-of-an-era/
2•harscoat•18m ago•0 comments

Un-Employ Us All

https://thunkpoorly.bearblog.dev/un-employ-us-all/
3•speckx•18m ago•1 comments

A dystopian world where LLMs can't code but can generate software binaries

https://twitter.com/random_walker/status/2082163285588107752
2•eamag•20m ago•1 comments

Tired of paying per domain for DMARC, so I built a self-hosted one

https://github.com/pescheckit/dmarc-service
2•botw44•24m ago•1 comments

10x Faster Change Management. Compliance Included

https://eng.miragesecurity.ai/posts/10x-change-management/
1•cebert•24m ago•0 comments

AI Companies Mass Shredding Rare Books [video]

https://www.youtube.com/watch?v=8c8pmp_OC2s
2•Bender•24m ago•0 comments

In-House LLM Serving at Netflix

https://netflixtechblog.com/in-house-llm-serving-at-netflix-a5a8e799ea2c
1•theanonymousone•30m ago•0 comments

Best 4K IPTV service Reddit: what the threads recommend

https://4kliveiptv.tv/
1•hunter_lewis754•31m ago•0 comments

The Maxwell Conjecture Is False (GPT 5.6 Sol)

https://arxiv.org/abs/2607.27197
2•rahen•33m ago•3 comments

Show HN: PinAllWindows – sync pinned apps across Chrome windows

https://chromewebstore.google.com/detail/pinallwindows/fakbifeeblnopdhicpmhhmcdhmefphjp
2•boundless88•34m ago•0 comments

You have been mislead about lightbulbs

https://maurycyz.com/misc/tungsten/
2•tonyg•36m ago•1 comments

Low Entropy Vuln on Coldcard Mk3 Hardware Wallets, 1082.58 BTC Drained

https://www.reddit.com/r/Bitcoin/comments/1vatgl4/full_panic_one_of_my_wallets_was_drained/
2•svenfaw•36m ago•0 comments

LinkedIn adds a 'Seems like AI slop' button

https://thenextweb.com/news/linkedin-seems-like-ai-slop-button
7•thunderbong•37m ago•2 comments