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Showing posts from December 22, 2018

Rotation invariant fingerprinting

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14 Imagine we have some polyomino and would like to uniquely identify them, however the polyominos can be rotated, so blindly hashing them won't give us the same fingerprint for a piece and a rotation thereof (in general). For example if we have the L-tetromino x x xx we would like it to have the same fingerprint as any of these: xx x x xxx xxx , x or x Note: We only allow rotations on the plane (ie. they are one-sided polyominos) and therefore the following polyomino would be a different one: x x xx Challenge The task for this challenge is to implement a fingerprinting-function/program which takes an $mtimes n$ Boolean/ $0,1$ -valued matrix/list of lists/string/.. encoding a polyomino and returns a string - the fingerprint of a polyomino. The fingerprint must