An polyomino is a non-empty connected subset of the square tiling consisting of squares joined along their edges. We will not require that polyominos be simply connected, that is they can have holes.

A bisection of a polyomino $X$ is a pair of polyominos such that they can be joined together without overlap to form $X$.

For example

XXXX
  XXX
   X

Can be bisected into:

XXX

and

 X
XXX
 X

since they can be joined as follows:

1112
  222
   2

Task

Your task is to take a polyomino as input and output the number of distinct bisections which can be made. Two bisections are distinct if the border between the parts is distinct. So

11
22

and

12
12

Are distinct bisections even though they share a rotational symmetry. But

11
22

and

22
11

are not distinct because the only difference is how you label the two parts.

This is code golf the goal is to minimize the size of your source code as measured in bytes

Test cases

X -> 0

XX -> 1

XXX -> 2

XXXX -> 3

XXXX -> 4
 X

XXXX -> 8
 XX

XX -> 6
XX

XX  -> 6
X X
XXX

XXX -> 28
X X
XXX

posted 11 months ago

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WheatWizard‭

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