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.

Uber pledges $10B to win robotaxi race

https://www.ft.com/content/04d6fcb4-03e4-4ee5-9017-ccaa7808c934
1•JumpCrisscross•30s ago•0 comments

The Importance of a Problem List

https://mathinstitutes.org/highlights/the-importance-of-a-problem-list
2•frozenseven•4m ago•0 comments

What Happened to Talenti?

https://www.nytimes.com/wirecutter/reviews/talenti-investigation/
2•jerlam•5m ago•0 comments

Notice of ICANN .bitcoin TLD community application

https://twitter.com/wiz/status/2085029140453830725
1•greyface-•5m ago•0 comments

SEC Establishes Financial Reporting and Accounting Unit in Enforcement Division

https://www.sec.gov/newsroom/press-releases/2026-72-sec-establishes-financial-reporting-accountin...
1•petethomas•6m ago•0 comments

Show HN: No-Bullshit CRM – Fast, simple and local

https://crm.cintracomunicacao.com.br/
1•danhdsss•10m ago•1 comments

Klaviyo Acquires Agency

https://techcrunch.com/2026/08/05/klaviyo-acquires-elias-torres-agency-in-full-circle-reunion-for...
1•krm01•10m ago•0 comments

Is Muse Code a Claude Code Killer?

https://trycodus.com/blog/muse-code-vs-claude-code-benchmarks
1•feryuk•10m ago•1 comments

The Nix sandbox is a hidden input

https://fzakaria.com/2026/07/30/the-nix-sandbox-is-a-hidden-input
2•birdculture•10m ago•0 comments

I have disabled NPM publishing on all projects that have been affected

https://twitter.com/jaredwray/status/2085084489408294921
2•trelane•11m ago•0 comments

The Knowledge Gap: what security awareness training achieves

https://safeinstinct.com/whitepapers/the-knowledge-gap-2026/
1•gabriel_b•13m ago•1 comments

Toast IDE Launches Standalone Alpha Mac App

https://github.com/paradise-runner/toast
1•dividedcomet•13m ago•1 comments

FDIC Floats Standard-Setting Body for Banks' Fintech Partners

https://news.bloomberglaw.com/banking-law/fdic-floats-standard-setting-body-for-banks-fintech-par...
1•petethomas•14m ago•0 comments

Cookies Became the Web's Memory

https://www.makonea.com/en-US/blog/how-cookies-became-the-web-s-memory
2•jdw64•14m ago•0 comments

Incentives Are for Losers

https://www.experimental-history.com/p/incentives-are-for-losers
2•dcminter•16m ago•0 comments

Ask HN: What do you think about Northstar-browser?

2•roschdal•19m ago•4 comments

NVMe polishes its specs, brings virtualization to locally attached SSDs

https://www.theregister.com/storage/2026/08/04/nvme-polishes-its-specs-brings-virtualization-to-l...
1•emptybits•19m ago•0 comments

Go: A more robust proposal process

https://github.com/golang/go/discussions/80580
1•fractorial•21m ago•0 comments

AI moderators won't run discovery interviews for another ten years

https://blog.zernote.com/ai-moderators-ten-years/
2•mironn•22m ago•0 comments

Show HN: Capy – A Git-style platform for managing your team's secrets

https://github.com/capysc/capy-cli
6•cvince•24m ago•3 comments

Traditional economics is wrong: Donald Trump has proved it

https://eastangliabylines.co.uk/business/economics/traditional-economics-is-wrong-donald-trump-ha...
2•SideburnsOfDoom•26m ago•0 comments

U.S. Cuts Ties with Organ Donor Group After Reports of Abuses

https://www.nytimes.com/2026/08/05/us/organ-donations-kentucky.html
2•JumpCrisscross•29m ago•0 comments

Classified cancer treatment research with parasites released after 60 years

2•yde_java•30m ago•0 comments

A probability grid of chain-of-thought, read through Boyd's OODA loop lens

https://adamsohn.com/reasoning-grid/
1•dataviz1000•31m ago•0 comments

Notes from the AI Coding Transition

https://emschwartz.me/notes-from-the-ai-coding-transition/
1•emschwartz•31m ago•0 comments

Month on Vegan Diet Shifts Epigenetic Patterns Assoc with Aging and Inflammation

https://today.ucsd.edu/story/one-month-on-a-vegan-diet-shifts-epigenetic-patterns-associated-with...
3•littlexsparkee•31m ago•0 comments

Ambient Lighting on Your Mac

https://www.trylumn.xyz/
2•arkancharla•31m ago•0 comments

Le Monde's 100 Books of the Century

https://en.wikipedia.org/wiki/Le_Monde%27s_100_Books_of_the_Century
3•chistev•32m ago•1 comments

Why cloning an app with vibe coding is doomed to fail

https://livablesoftware.com/why-cloning-an-app-with-vibe-coding-fails/
3•softmodeling•33m ago•0 comments

I'm switching my phone from Android to Linux

https://runarcn.no/android-to-linux/
2•speckx•34m ago•1 comments