Various ports of this dungeon generator: https://gist.github.com/ctsrc/fef3006e1d728bb7271cff0656eb0280#file-dungeon-c
dungeon.html
Written by someone else; though I added some querystring configuration
dungeon.ex
Implementation of the generator using a List as the structure that holds the dungeon being generated. A list is not good for random access and very slow for this problem.
dungeon2.ex
Similar, but instead of a List a Map is used. Much faster than the List version as only certain specific elements need checked/changed (ie, much faster with the random access)
dungeon3.ex
Using more recursive methods and less for statements. Also modified some of the logic around generating a room and not checking based on the coordinate what a particular tile should be (since the rooms are rectangular this information is easily calculated).