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Rubik's Cube Algorithm Cut Again, Down to 23 Moves

Posted by timothy on from the at-this-rate-one-will-soon-be-enough dept.

Bryan writes "The number of moves necessary to solve an arbitrary Rubik's cube configuration has been cut down to 23 moves, according to an update on Tomas Rokicki's homepage (and here). As reported in March, Rokicki developed a very efficient strategy for studying cube solvability, which he used it to show that 25 moves are sufficient to solve any (solvable) Rubik's cube. Since then, he's upgraded from 8GB of memory and a Q6600 CPU, to the supercomputers at Sony Pictures Imageworks (his latest result was produced during idle-time between productions). Combined with some of Rokicki's earlier work, this new result implies that for any arbitrary cube configuration, a solution exists in either 21, 22, or 23 moves. This is in agreement with informal group-theoretic arguments (see Hofstadter 1996, ch. 14) suggesting that the necessary and sufficient number of moves should be in the low 20s. From the producers of Spiderman 3 and Surf's Up, we bring you: 2 steps closer to God's Algorithm!"

30 of 202 comments (clear)

  1. I still can't do it. by ASMworkz · · Score: 5, Funny

    Call me when it's down to 10 moves! :)

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    1. Re:I still can't do it. by Hankapobe · · Score: 5, Funny

      Call me when it's down to 10 moves! :)

      I can do it in one .... I outsource it.

    2. Re:I still can't do it. by Kjella · · Score: 5, Funny

      I can do it in zero, I just declare that it's fine just the way it is and accuse anyone that tries to argue otherwise for being segregationists trying to keep all the different colors apart.

      --
      Live today, because you never know what tomorrow brings
    3. Re:I still can't do it. by fizzup · · Score: 4, Funny

      Call me when it's down to 10 moves! :)

      I can do it in one .... I outsource it.

      I can solve it faster .... I defenestrate it.

    4. Re:I still can't do it. by Daimanta · · Score: 4, Funny

      Yes, but does the window run Linux?

      Please, disregard the previous sentence.

      Please, disregard the previous sentence.

      --
      Knowledge is power. Knowledge shared is power lost.
    5. Re:I still can't do it. by Herkum01 · · Score: 3, Funny

      When I was a kid I had a rubix cube which one day resulted in this,

      Angry Kid + Teacher(target) + Rubix Cube = defenestrate + one half rubix cube + dozens little pieces of a cube.

      Afterwards I felt pretty bad about the whole thing...

    6. Re:I still can't do it. by Fishead · · Score: 4, Funny

      I like to buy a new one, solved, and in the package, then using some CA (krazy glue) glue it together so nobody can "un-solve" it.

    7. Re:I still can't do it. by khallow · · Score: 3, Funny

      This method has firm group theoretic underpinnings too. An alternate way to view this excellent solution is to realize that moves don't matter. Thus, you can say all states of the Cube linked by moves are equivalent in their state of fineness and hence the entire orbit is a single equivalence class of acceptability. This reduces the overly complex and uninteresting problem to a trivial one. Perfectly mathematical thing to do.

    8. Re:I still can't do it. by this+great+guy · · Score: 3, Funny
      What did the verb "defenestrate" apply to ?
      • 1. the cube
      • 2. the kid
    9. Re:I still can't do it. by SQLGuru · · Score: 4, Funny

      This post intentionally left blank

  2. That's quick by ricebowl · · Score: 5, Funny

    And here I used to think my method was faster; but since there's more than 23 stickers on the cube I guess it ain't any more...

    1. Re:That's quick by Hankapobe · · Score: 3, Funny

      And here I used to think my method was faster; but since there's more than 23 stickers on the cube I guess it ain't any more...

      Try spray paint.

    2. Re:That's quick by Tumbleweed · · Score: 4, Funny

      And here I used to think my method was faster; but since there's more than 23 stickers on the cube I guess it ain't any more...

      This would definitely faster than my method of taking it apart and reassembling it in the correct order.

    3. Re:That's quick by Chris+Burke · · Score: 5, Funny

      I just buy a new one.

      --

      The enemies of Democracy are
  3. I can always do it.... by Brad1138 · · Score: 4, Funny

    in 48 moves or less. Luckily the center sticker is always in the right place so I don't need to move that one.

    --
    If you could reason with religious people, there would be no religious people
  4. LET THERE BE THREE moves... by davidsyes · · Score: 3, Funny

    1. Pour paint on Cube
    2. Let Dry
    3. PROPHET

    --
    Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
    1. Re:LET THERE BE THREE moves... by GoodNicksAreTaken · · Score: 4, Funny

      3. PROPHET
      That must be part of the God's algorithm the summary mentions.
  5. Re:Solvable? by pwnies · · Score: 5, Funny

    It may not be a rubiks cube, but it would be quite humorous if strategically placed in an "Obsessive Compulsive Puzzle Solvers Anonymous" meeting.

  6. I can do it in 2... by El_Oscuro · · Score: 3, Funny
    1. Take apart
    2. Put back together (wait... why are there parts left over????)
    --
    "Be grateful for what you have. You may never know when you may lose it."
  7. Only one move required... by FoolsGold · · Score: 5, Funny

    Blend the fucker - http://www.youtube.com/watch?v=NrqHHBibRvs

    There, saved you from another 22 pointless moves.

  8. Re:Solvable? by Deanalator · · Score: 2, Funny

    I once spent and hour or so working on a cube before I realized that one of the two color pieces had two colors from opposite sides of the cube :-(

    It is pretty annoying when people do the sticker trick to only solve one side of a cube.

  9. Easy by camperdave · · Score: 4, Funny

    Call me when it's down to 10 moves!

    Step 1: Drop cube in can of paint. Done.

    --
    When our name is on the back of your car, we're behind you all the way!
    1. Re:Easy by felipekk · · Score: 2, Funny

      Actually, that's more than 10 moves:

      1 Drive to Home Depot
      2 Buy bucket and paint
      3 Drive back home
      4 Open the paint enclosure
      5 Drop paint into bucket
      6 Clean the floor
      7 Clean yourself
      8 Drop the cube
      9 Pickup the cube
      10 Realize that white paint won't make it look solved
      11 Drive back to Home Depot
      12 Buy a new bucket and dark paint
      13 Drive back home
      14 Open
      15 Drop
      16 Clean yourself (you actually learned not to mess the floor)
      17 Drive to Toys-R-Us
      18 Buy another Rubik's cube
      19 Drive back
      20 Drop the cube
      21 Pick it up

      Solved!

    2. Re:Easy by KDEWolf · · Score: 1, Funny

      Call me when it's down to 10 moves! Step 1: Drop cube in can of paint. Done. Step 2: ?????

      Step 3: Profit!
    3. Re:Easy by Jay+L · · Score: 2, Funny

      Drop cube in can of paint.

      Paint is so 1987. Sears now sells powder coaters for $150.

      There is nothing that can't be improved with a little powder coating. Pencils, silverware, desks...

  10. Re:Solvable? by Fred+Ferrigno · · Score: 3, Funny

    My friends decided to flip two pieces without telling me, thinking that would really annoy me. They were quite disappointed when I solved the cube, as the second flip perfectly counteracted the effect of the first.

  11. Do the math, quick! by HiggsBison · · Score: 5, Funny

    And here I used to think my method was faster; but since there's more than 23 stickers on the cube I guess it ain't any more...

    So that would be, um, each face is three by three, um, nine stickers on each face. Then multiply that times the number of sides, so six times nine would be, uh, ...

    Forty two.

    --
    My other car is a 1984 Nark Avenger.
    1. Re:Do the math, quick! by something_wicked_thi · · Score: 2, Funny

      No.

      It's 42.

      Trust me.

  12. my best time -1 min by ami.one · · Score: 5, Funny

    As a kid my best time was 1 min ! Used to just take off all the stickers on all faces and put them back in correct order. Friends were confused though as to why i want to solve it alone in a room and not in front of them.

  13. Re:Or... by this+great+guy · · Score: 4, Funny
    You could share the script you used to output that sentence...

    #!/bin/sh echo "Or 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19 or and 20 moves."