For 7DRL this year I developed a new map generation algorithm called Pigeon Hole Stepping.
Fill the map with walls
This map generation algorithm relies on negative building techniques. This concept will make more sense as the later steps are explained.
Essentially, we can assume that hallways that are parallel to each other are at least the length of a single room and up to two rooms apart in distance. Because of this assumption, we can make a random walker that will move around with this restriction in mind until map is filled completely.