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.

Gemini Hacked Three Companies in First Known Breakout by Google's AI

https://www.wsj.com/tech/ai/gemini-hacked-three-companies-in-first-known-breakout-by-googles-ai-5...
1•berkeleyjunk•5m ago•0 comments

Hacker News Firehose for iOS

https://blog.harrison.page/hacker-news-firehose-ios/
1•harrisonpage•5m ago•1 comments

US and Denmark reach deal over Greenland security

https://www.bbc.co.uk/news/articles/c63d7lexyym1o
2•squirrel•7m ago•0 comments

Flox will require login for search/install commands starting in October

https://flox.dev/docs/concepts/authentication
1•Evidlo•9m ago•0 comments

Open source tool to schedule, analyze, and grow your LinkedIn page

https://github.com/yapsgg/linkedin-growth
1•abdibrokhim•10m ago•0 comments

Could we reboot the modern world without fossil fuels?

https://aeon.co/essays/could-we-reboot-a-modern-civilisation-without-fossil-fuels
1•paimapi•10m ago•0 comments

How the Boeing 737 MAX Disaster Looks to a Software Developer (2019)

https://spectrum.ieee.org/how-the-boeing-737-max-disaster-looks-to-a-software-developer
2•chmaynard•11m ago•1 comments

Qantas is retiring its A380s

https://www.cnn.com/2026/09/13/travel/qantas-a380-superjumbo-retirement-goodby
1•simonebrunozzi•12m ago•0 comments

SAIR's Open Math Model Initiative

https://terrytao.wordpress.com/2026/09/18/sairs-open-math-model-initiative/
1•JohnHammersley•13m ago•0 comments

Anthropic Shifts Planned IPO to November

https://www.wsj.com/tech/ai/anthropic-shifts-planned-ipo-to-november-8874dffc
2•qlte•16m ago•0 comments

Brian Greene interviews Stephen Wolfram: Can spacetime emerge from simple rules? [video]

https://www.youtube.com/watch?v=yAJTctpzp5w
2•lioeters•21m ago•0 comments

Steve Eisman on AI: Companies are trying to manufacture a crisis

https://www.youtube.com/watch?v=4qV5WWgFTS8
3•Betelbuddy•24m ago•1 comments

A 6502 emulator written in Markdown (and executed by an LLM)

https://dunkels.com/adam/llm-6502-emulator/
2•adunk•24m ago•0 comments

ATRA-mediated RAR-α activation attenuates acrylamide-induced testicular toxicity

https://www.nature.com/articles/s41598-026-50168-z
1•harry_nutsachs•25m ago•0 comments

The White House Tussle to Sway Trump on AI

https://www.wsj.com/tech/ai/inside-the-white-house-tussle-to-sway-trump-on-ai-0043d567
1•Topfi•26m ago•0 comments

Two parallel neural ectoderm progenitors contribute to the developing brain

https://www.nature.com/articles/s41593-026-02433-7
1•gone35•26m ago•0 comments

Anthropic is planning to launch its IPO in November

https://www.wsj.com/tech/ai/anthropics-ipo-will-happen-a-month-later-than-expected-a334b10e
2•mfiguiere•29m ago•1 comments

Valve has open-sourced Lepton, its tool to bring Android games to Steam

https://www.theverge.com/tech/997315/valve-has-open-sourced-lepton-its-tool-to-bring-android-game...
3•robotnikman•31m ago•0 comments

Exclusive-Anthropic sets up biology lab as it ramps AI drug program

https://finance.yahoo.com/healthcare/articles/exclusive-anthropic-quietly-sets-biology-100133604....
1•tortilla•31m ago•0 comments

I Hate Workday

https://nelson.cloud/i-hate-workday/
2•lr0•31m ago•1 comments

Y Combinator's PAC is throwing money at Republicans across the country

https://sf.gazetteer.co/y-combinators-pac-is-throwing-money-at-a-bunch-of-republicans-across-the-...
38•slater•32m ago•10 comments

War may be coming. Are we psychologically ready?

https://www.bbc.com/news/articles/cmn0jke547r5o
27•meep_meep_meep•32m ago•29 comments

Flawed AI Intel Brought US to the Brink of Confronting China, Claims Report

https://www.ndtvprofit.com/world/almost-started-a-war-flawed-ai-intel-brought-us-to-the-brink-of-...
2•theanonymousone•34m ago•0 comments

AI cloud provider Nscale files for IPO on $140.6M revenue, $1.02B net loss

https://www.cnbc.com/2026/09/18/nscale-ai-cloud-provider-ipo-nscl.html
2•ilamont•36m ago•0 comments

Show HN: Find Street Parking in NYC

https://parking.avi.nyc/
1•aviflombaum•38m ago•0 comments

Software-Based Live Migration for RDMA – Proceedings of the ACM Sigcomm 2025

https://dl.acm.org/doi/10.1145/3718958.3750487
1•rbanffy•39m ago•0 comments

Anthropic sets up a bio research lab for physical experiments

https://www.engadget.com/2262087/anthropic-has-set-up-a-bio-research-lab-for-physical-experiments/
5•armcat•41m ago•3 comments

Show HN: Prohibition of Nuclear Launch Automation

3•healthworker•45m ago•0 comments

A CPU Backdoor (2025)

https://phrack.org/issues/72/a-cpu-backdoor_md
3•yu3zhou4•45m ago•0 comments

Show HN: TypeSeer – on-device autocomplete for every text field on macOS

https://typeseer.com/
1•animateus•47m ago•1 comments