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.

Ryanair CEO compares rival airlines to 'rapists'

https://www.brusselstimes.com/2312302/ryanair-ceo-compares-rival-airlines-to-rapists
1•Daniyal45•2m ago•0 comments

Marriott Guest Says Hotel Insisted a Rubbermaid Laundry Cart Was a Baby Crib

https://www.fashiontimes.co.uk/marriott-guest-rubbermaid-cart-instead-crib-1763854
1•extasetoi12•4m ago•0 comments

Homebrew 7.0.0

https://brew.sh/2026/09/13/homebrew-7.0.0/
1•mikemcquaid•6m ago•1 comments

Man arrested after allegedly sexually abusing koi fish in Bangkok

https://www.khaosodenglish.com/featured/2026/09/11/man-arrested-after-allegedly-sexually-abusing-...
1•face2sunny•7m ago•0 comments

Robots protest in Poland over AI regulation concerns

https://www.aljazeera.com/video/newsfeed/2026/9/7/robots-protest-in-poland-over-ai-regulation-con...
1•dinesshsaini21•9m ago•0 comments

Toposes are NOT scary – Urs Schreiber [video]

https://www.youtube.com/watch?v=_3TslhCBQ1E
1•hackandthink•10m ago•0 comments

Download More RAM – Nvidia CMP 170HX Cmpunlocker

https://www.lttlabs.com/articles/2026/09/12/cmp-170hx-cmpunlocker
1•willx86•14m ago•0 comments

In Clover: What does McKinsey do? (2022)

https://www.lrb.co.uk/the-paper/v44/n24/laleh-khalili/in-clover
1•Tomte•19m ago•0 comments

Show HN: Run coding agents on your own machine, steer them from anywhere

https://github.com/phyra-research/roamux
2•mwiki•26m ago•0 comments

Diablo 5 Announced

https://sea.ign.com/diablo-iv/248747/diablo-5-announced
1•nsoonhui•27m ago•0 comments

Ask HN: Should we start airgapping our personal devices?

1•emerongi•27m ago•1 comments

Android – Morphe patch app list

https://morphe-patches.software/#apps
1•dockerd•28m ago•0 comments

Deepfakes are wrecking influencers' credibility, one fake ad at a time

https://www.theguardian.com/technology/2026/sep/12/deepfakes-wrecking-influencers-credibility
3•andsoitis•31m ago•1 comments

Genuine curiosity will always beat performative intellectualism

https://hasifcore.substack.com/p/genuine-curiosity-will-always-beat
3•the-mitr•32m ago•0 comments

Rawtree – A ClickHouse Fork by Tinybird

https://rawtree.com/
2•knuckleheads•32m ago•0 comments

Matt Berry is now a sentient IKEA shelf in Skyrim

https://www.pcworld.com/article/3233287/matt-berry-is-now-a-sentient-ikea-shelf-in-skyrim.html
1•jubayer9906•36m ago•0 comments

Ask HN: What if anyone could sell AI tokens from their idle GPU?

1•edurights-team•36m ago•2 comments

Show HN: How LLMs work, explained through music, football or cricket analogies

https://understand-ai.dev/
1•understandaidev•36m ago•0 comments

Persimmon v0.1 Model Card

https://persimmon.humansand.ai/blog/persimmon-model-card.html
1•pr337h4m•36m ago•0 comments

Little Tikes iconic children's toys go colorless for 'contemporary feel'

https://www.wafb.com/2026/09/10/little-tikes-iconic-childrens-toys-go-colorless-contemporary-feel/
2•Danhale93•38m ago•0 comments

Dramatic insider warnings over AI fall flat with some in Silicon Valley

https://www.bbc.co.uk/news/articles/cq635037g18o
10•chrisjj•39m ago•3 comments

Texts Reveal Kash Patel Ordering Staff to Fight "Ifindretards" Account

https://newrepublic.com/post/215320/texts-kash-patel-order-staff-mean-social-media-posts-ifindret...
3•girish_r•40m ago•0 comments

Massing

https://en.wikipedia.org/wiki/Massing
1•tosh•49m ago•0 comments

This website runs on a Raspberry Pi 4B with only 1 GB of RAM

https://pi.deepakness.com/
3•7777777phil•51m ago•1 comments

Pace the frontier but stop pretending you need anyone else's permission

https://twitter.com/DavidSacks/status/2098973625252708460
1•caaqil•53m ago•0 comments

Software Engineer: I'm Tired of Pretending [video]

https://www.youtube.com/watch?v=H0HwFqBG9KE
3•conferza•55m ago•0 comments

OpenAI built a text generator so good, it's considered too dangerous (2019)

https://techcrunch.com/2019/02/17/openai-text-generator-dangerous/
8•olalonde•56m ago•1 comments

Keep calm and regulate on: Inside the EU's response to AI extinction warnings

https://www.politico.eu/article/eu-response-ai-extinction-warnings/
3•vrganj•56m ago•1 comments

Monitoring Mint with Microcontrollers Running TinyGo

https://www.mrnice.dev/posts/monitoring-mint-part-1/
1•ShayNehmad•56m ago•1 comments

JetKVM Mini

https://jetkvm.com/blog/introducing-jetkvm-mini
35•taubek•57m ago•15 comments