I'm currently developing a city builder with a zoning system similar to Cities  : Skylines. What I would need is an algorithm that would find all the way to fill this grid (in red) but with some constraints  : In this case, one way to fill it would be to have a building on the left (size 4x3) and one building one the right (size 3x4). But to have some variety, I don't want to always minimize the number of buildings, so in this case I would like also to allow 2 buildings of 2x3 on the left + 1 building of 3x4 on the right. Someone pointed me toward the Dancing Links algorithm to solve this.  

I'm developing a city builder with a zoning system similar to Cities: Skylines. What I would need is an algorithm that would find all the way to fill this grid (in red) but with some constraints: In this case, one way to fill it would be to have a building on the left (size 4x3) and one building one the right (size 3x4). But to have some variety, I don't want to always minimize the number of buildings, so in this case I would like also to allow 2 buildings of 2x3 on the left + 1 building of 3x4 on the right. Someone pointed me toward the Dancing Links algorithm to solve this.