3 ms·
The good thing about normal combination locks is that you can try all combinations sequentially with minimum movement. 000 start 001 1 move 002 1 move
by emilfihlman 7y ago
The good thing about normal combination locks is that you can try all combinations sequentially with minimum movement.
000 start
001 1 move
002 1 move
...
008 1 move
009 1 move
019 1 move
018 1 move
...
011 1 move
010 1 move
020 1 move
021 1 move
...
and so on.
- kozhevnikov 7y agoI feel like saving 1 move in 10 (9 to 10 is 2 moves, 10 to 11 is back to 1 move) is not worth the mental capacity required to remember current up/down direction. Easier to let the muscles do the work and let your mind wonder.
- emilfihlman 7y agoThat's a good point, though I do think that it's not that big of a mental hurdle. Consider knitting, for example.
- rvdse 7y agoThat sounds similar to the concept of Gray code [0]. For electronic locks, there is a similar method that allows you to try a 4-digit code for each key press [1]. [0] https://en.wikipedia.org/wiki/Gray_code https://en.wikipedia.org/wiki/Gray_code [1] http://alvaray.org/brute-forcing-pincode-keypads-using-combinatorial-mathematics/ http://alvaray.org/brute-forcing-pincode-keypads-using-combi...
- emilfihlman 7y agoYup, that's the general idea I also had in mind. Those "try all n in shortest combination" sequences are called De Bruijn sequences in general. https://en.wikipedia.org/wiki/De_Bruijn_sequence https://en.wikipedia.org/wiki/De_Bruijn_sequence
- Ductapemaster 7y agoThese codes have been used to break wireless garage door openers in comically little time: https://samy.pl/opensesame/ https://samy.pl/opensesame/
- darkpuma 7y agoIn practice 009 to 010 is a single move, because your thumb can cover and turn two or more wheels at once.