[periodontal]

This is a specific example of an Exact cover problem: https://en.wikipedia.org/wiki/Exact_cover

If you haven't seen Knuth's Dancing Links implementation of Algorithm X, I highly recommend it. It's based on the observation that updating a doubly-linked list in-place preserves enough information to make backtracking easy.

[kybernetikos]

My JS implementation is http://dancing-links.herokuapp.com/

It includes a sudoku (also exact cover) and pentonimo solver.

[carapace]

This make me want to dig up a version I did in Python (for Sudoku as it happens.) The algorithm is a bad fit for Python because attributes are not pointers, but have a look at this:

http://www.cs.mcgill.ca/~aassaf9/python/algorithm_x.html

> One day I decided to write Algorithm X in Python, and I came up with a very interesting variation on Dancing Links.

[kybernetikos]

That's really fun.

[jxramos]

I feel like I may be missing something in comprehending that first up mathematical definition in the Exact cover wiki. How is it different from a partition of a set? (https://en.wikipedia.org/wiki/Partition_of_a_set).

UPDATE: think I may see it, sounds like in terms of partitions an exact cover is a subset of a set's partition.

[denfromufa]

wow, this is insightful generalization