| The scrambling program tnoodle is open source and you can check out the implementation. [0] I haven't verified myself, but I do think there is checking involved for some of the events (at least 3x3, 2x2, skewb, square-1, and pyraminx) to make sure the puzzles hit the minimum move limit. Other events like 5x5+ just use a sufficient number of random moves, because it would take too long to find and verify optimal solutions. I can say in practice that the 2 move limit for 3x3 isn't a problem. I work on some personal projects related to cubing and was exploring the database [1] which has many historical scrambles. The shortest scramble ever generated was 12 moves long [2], and, from what I could tell from an extended inspection, is only "kind of" lucky. It's possible that some other simpler solves exist in the database but I haven't set my computer to crunch out the optimal solutions just yet. I'm not particularly worried about really-short scrambles being randomly generated; my back of the envelope calculations suggest 3x3 scrambles of 8 moves or less as being one in 3.6 billion, while ~310,000 have been generated since 2014 and I estimate a seventh of them are never used (extra scrambles generated for a round if something goes wrong like the timer malfunctioning, the judge not following protocol, etc.). [0] https://github.com/thewca/tnoodle [1] https://www.worldcubeassociation.org/results/misc/export.htm... [2] https://www.worldcubeassociation.org/competitions/SofiaAutum... |