Subtraction.com

Solving the Rubik’s Cube in Twenty Moves or Less

A mathematician from Kent State University, an engineer at Google, a math teacher from Darmstadt, Germany, and a programmer from Palo Alto, California arrive at some definitive conclusions regarding the thirty-six year old Rubik’s Cube puzzle:

“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… 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.”

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