According to Erno Rubik, founder of the Rubik’s cube
:
:“A good puzzle, it's a fair thing. Nobody is lying. It's very clear, and the problem depends just on you”
The first inspiration to learn how to solve the cube for me was after I watched -The Pursuit of Happiness
- movie. I use the Rubik's Cube as a stress reliever, I can never be bored of it, my best time to solve was around 2 minutes; however, the world record to solve is 6.65 seconds.
- movie. I use the Rubik's Cube as a stress reliever, I can never be bored of it, my best time to solve was around 2 minutes; however, the world record to solve is 6.65 seconds.Before we go deeper, here you can find the algorithms to solve the Rubik's Cube , and you can find a lot of youtubes explaining it in a very simple way.
An international team of researchers using computer time lent to them by Google has found every way the popular Rubik's Cube puzzle can be solved. The study is just one of the plethoras of attempts by Rubik's enthusiasts to figure out the mysteries of the cube, which has proven to be altogether far more complicated that its debonair colors might suggest. The study builds on the work of a veritable pantheon of Rubik's researchers, starting with Morwen Thistlethwaite who in 1981 showed 52 moves were sufficient to reach the solution from any given Cube position.
Ever since Erno Rubik conceived the Rubik's Cube in 1974, math-minded enthusiasts have been trying to find the most efficient number of moves required to solve the 3x3 Rubik's Cube in any script, which they refer to as "God's Algorithm". And in God's Algorithm, the maximum number of moves for the worst case scenario has finally been solved—"God's Number" is 20.
The minimum number of moves reduced to 42 by the period of 1992 and by 2005 this number reduced to 28 but still the enthusiasts were looking for the perfect minimum solution which was termed as God’s Number and it was believed that no less than God’s algorithm would be able to solve it.
There are exactly 43,252,003,274,489,856,000 permutations of Rubik’s cube which is an unimaginable number to solve out. Any one of the movement pattern out of 43,252,003,274,489,856,000 permutations can be used to make up the cube. It was really challenging to define the number of moves required to cover any of the arrangement to make up the cube.
So, how did a Google engineer, a Kent State mathematician, a German math teacher and a Californian programmer crack the code?
According to them,
“We partitioned the positions into 2,217,093,120 sets of 19,508,428,800 positions each. We reduced the count of sets we needed to solve to 55,882,296 using symmetry and set covering. We did not find optimal solutions to each position, but instead only solutions of length 20 or less. We wrote a program that solved a single set in about 20 seconds of time. We used about 35 CPU years to find solutions to all of the positions in each of the 55,882,296 sets”.
The "Superflip" (left) was the first position ever found with 20 moves.
"It took fifteen years after the introduction of the Cube to find the first position that irrefutably requires twenty moves to solve; it is appropriate that fifteen years after that, we prove that twenty moves suffice for all positions."
For more details, here you can find the team of researchers website
