Now posted: Label a hinged tetromino

Given a hinged tetromino, give it a unique, consistent label.

Tetrominoes

A tetromino is a connected subset of the square tiling, composed of 4 squares, where connection can only be edge connection.

Here are the 5 tetrominoes:

Hinged tetrominoes

A hinged tetromino is a connected subset of the square tiling, composed of 4 squares, where connection can be edge connection or corner connection.

Here are the 22 hinged tetrominoes:

Input

• A 4 by 4 grid containing a hinged tetromino.
• You may take input in any convenient format that does not include full or partial precalculation.
• For example, this could be a string or sequence of strings, a 1 or 2 dimensional list/array/vector, a sequence of coordinates, or a 16 bit variable where each 1 bit represents part of the hinged tetromino and each 0 bit represents part of the background. A variable with more than 16 bits where only 16 of the bits are used would also be acceptable.

Output

• A label for the hinged tetromino.
• The label for each hinged tetromino can be anything you choose, including nothing (no output).
• Each label must be unique (it must not be the label for any other hinged tetromino).
• Each label must be consistent (a given hinged tetromino must always result in the same label, regardless of rotation, reflection, or translation).

Scoring

This is a code golf challenge. Your score is the number of bytes in your code.

Explanations are optional, but I'm more likely to upvote answers that have one.

posted over 1 year ago

CC BY-SA 4.0

1y ago

trichoplax‭

1050 reputation 83 17 132 472