Rubik's-Cube

精品文档Rubiks CubeI think almost everyone know this toy. And many people have tried to solve it. It is originally called the Magic Cube. When I was a little boy, my father give it to me, and he showed me how to recovery the first layer. At that time, I was amazed by that because no matter how hard I tried, I can only to make one surface in one color. So I try to find out how to solve the first layer. You see, it is difficult not to play Magic Cube when you first meet it.When I was growing up, I know more about Magic Cube. It is invented in 1974 by Hungarian sculptor and professor of architecture Rubik. It is widely considered to be the worlds bestselling toy. A standard Rubiks Cube measures 5.7cm on each side. The original Rubiks Cube has eight corners and twelve edges. Thus there are many possibilities. Do you know how many possibilities of Rubiks Cube? It is approximately 43 quintillion, eighteen zeros. So If you do not find a way to solve it, it is very hard to recovery by lucky.Many general solutions for the Magic Cube have been discovered independently. The most popular method was solving the cube layer by layer. This solution is also called seven-step method. Another solution, which is so-called CFOP, commonly used by speed cubers. The cross is done first followed by first-layer corners and second layer edges simultaneously, with each corner paired up with a second-layer edge piece, thus completing the first two layers (F2L). This is then followed byorientingthe last layer then permutingthe last layer (OLL and PLL respectively).CFOPrequires learning roughly 120 algorithms but allows the Cube to be solved in only 55 moves on average.As I say, there are some people try to solve a magic cube in the shortest time possible, we call them speedcubing. There are a number of speedcubing competition that take place around the world. So there are some records. Like as Single time, single shortest time to solve. It is 5.55s. Average time, the average minimum time. It is 6.54s. And shortly before, some engineers used the Galaxy S4 as robots processor within 4 seconds to recover a cube. This is the fastest record.In addition, people want to know how many moves can solve any magic cube at least. They used super computer proved the so-called Gods number to be 20. This is optimal, since there exist some starting positions which require at least 20 moves to solve.By the way, the magic cube that set the world record is invented by Chinese cuber Dayantou. The cubes structure is different from traditional one, but it