# Rubiks Cube

### From HaskellWiki

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Here is a simple model for a [http://en.wikipedia.org/wiki/Rubik%27s_cube Rubik's Cube]. |
Here is a simple model for a [http://en.wikipedia.org/wiki/Rubik%27s_cube Rubik's Cube]. |
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− | My hope is to get people to see a rubik's cube as something other than "a problem to solve." It's a toy! |
+ | The basic idea is that you only need to keep track of the corners and edges. Each corner has three faces. Each edge has two faces. Keeping track of a face means telling where it was before any moves were made and where it is in the current state. |

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− | My two ideas are to get people to play with Haskel code _about_ the cube and (a separate idea, maybe to be explored in this model later) to make cubes with five colors, each edge and corner having the same coloring as each other. These markings will implicitly encourage people to focus on the interesting questions of how and when corners rotate and edges flip |
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− | Before I started writing this, I spent months and months carying one, and sometimes several cubes around with me. I loved watching and thinking about how the different edges and corners would travel around the cube in relationship to each other. |
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− | The basic idea of this model (below) is that you only need to keep track of the corners and edges. Each corner has three faces. Each edge has two faces. Keeping track of a face means telling where it was before any moves were made and where it is in the current state. |
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Choose, as a convention, the ordering, right, up, front. (Math/Physics folk: this is in anology to the "right hand rule" convention which assigns an ordering to the "x y and z" axes and determines that z will be "out of" rather than "into" the plane) |
Choose, as a convention, the ordering, right, up, front. (Math/Physics folk: this is in anology to the "right hand rule" convention which assigns an ordering to the "x y and z" axes and determines that z will be "out of" rather than "into" the plane) |
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down front position would be represented as (Left Down) (Down Right) |
down front position would be represented as (Left Down) (Down Right) |
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(Front Front). |
(Front Front). |
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+ | Edit by somebody else: I'm not the author of this, however I think there are some erros in the definition of all the datas below. I think they all are missing the constructor, when you're reading the code keep that in mind. also: |
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+ | You can read the paper by Richard E. Korf named "Finding Optimal Solutions to Rubik's Cube Using Pattern Databases."[[1]] to have a better understanding of the Edged/Corners approach |
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<haskell> |
<haskell> |
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data Is = R|L|U|D|F|B |
data Is = R|L|U|D|F|B |
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</haskell> |
</haskell> |
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+ | [[[1]] [http://www.cs.princeton.edu/courses/archive/fall06/cos402/papers/korfrubik.pdf] |
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[[Category:Code]] |
[[Category:Code]] |

## Revision as of 22:48, 16 June 2010

Here is a simple model for a Rubik's Cube.

The basic idea is that you only need to keep track of the corners and edges. Each corner has three faces. Each edge has two faces. Keeping track of a face means telling where it was before any moves were made and where it is in the current state.

Choose, as a convention, the ordering, right, up, front. (Math/Physics folk: this is in anology to the "right hand rule" convention which assigns an ordering to the "x y and z" axes and determines that z will be "out of" rather than "into" the plane)

For example, the lower left front corner would be represented as (Left Left) (Down Down) (Front Front) before any moves are made Then, after a rotation about the Front face, the same corner, now in the right down front position would be represented as (Left Down) (Down Right) (Front Front).

Edit by somebody else: I'm not the author of this, however I think there are some erros in the definition of all the datas below. I think they all are missing the constructor, when you're reading the code keep that in mind. also:

You can read the paper by Richard E. Korf named "Finding Optimal Solutions to Rubik's Cube Using Pattern Databases."1 to have a better understanding of the Edged/Corners approach

#!/usr/bin/runhugs module Main (main) where main :: IO () main = do putStr "Not your ordinary language" data Cube = Edges Corners type Edges = [Edge] -- or Edges = Edge Edge Edge Edge Edge Edge Edge Edge Edge Edge Edge Edge type Corners = [Corner] data Edge = Face Face data Corner = Face Face Face data Face = Was Is data Was = R|L|U|D|F|B data Is = R|L|U|D|F|B

[[[1]] [1]