Light 发表于 2010-8-9 09:47:40

上帝之数是20!已被证明!

不小心看到Leyan Lo说的:网址:http://www.cube20.org/

粘点先:
Every position of Rubik's Cube™ can be solved in twenty moves or less.
With about 35 CPU-years of idle computer time donated by Google, a team of researchers has essentially solved every position of the Rubik's Cube™, and shown that no position requires more than twenty moves.

Every solver of the Cube uses an algorithm, which is a sequence of steps for solving the Cube. One algorithm might use a sequence of moves to solve the top face, then another sequence of moves to position the middle edges, and so on. There are many different algorithms, varying in complexity and number of moves required, but those that can be memorized by a mortal typically require more than forty moves.

One may suppose God would use a much more efficient algorithm, one that always uses the shortest sequence of moves; this is known as God's Algorithm. The number of moves this algorithm would take in the worst case is called God's Number. At long last, God's Number has been shown to be 20.

It took fifteen years after the introduction of the Cube to find the first position that provably requires twenty moves to solve; it is appropriate that fifteen years after that, we prove that twenty moves suffice for all positions……

kongmin 发表于 2010-8-9 09:50:13

沙发。。。。。。。。。。。。

无为子 发表于 2010-8-9 09:51:45

看不懂英文,如果是真的,这宗国际疑案那就画上了句号

scksck888 发表于 2010-8-9 09:52:42

全都20以下,人能算出来吗?

天花板上吊着猫 发表于 2010-8-9 09:57:38

电脑用穷举法把所有状态算完了。
证明所有状态都可以在20步及以内步还原。

Paracel_007 发表于 2010-8-9 10:03:21

穷举?穷举是个夸张的做法…

zbyxzh 发表于 2010-8-9 10:04:52

仔细研究一下原文。应该不是单纯的穷举。
如果每个魔方都算到最少步,以现在的计算机硬件水平估计是不现实的……
截张图:

[ 本帖最后由 zbyxzh 于 2010-8-9 10:43 编辑 ]

ursace 发表于 2010-8-9 10:05:38

是因为上帝看WR是22步,怕太没面子了,定到了20咩?:lol

ggglgq 发表于 2010-8-9 10:06:01

  
  
   
    感谢楼主及时提供资料 !
  
  
  
  

夜雨听风 发表于 2010-8-9 10:24:34

穷举法  这计算机要多少台  工作多久  我晕
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