Rubik cube algorithm seeker.

rubik.rb

require 'pp'

class Cube
    attr_accessor :cells

    def initialize
        @cells = {
            top: [0] * 9,
            front: [1] * 9,
            left: [2] * 9,
            right: [3] * 9,
            bottom: [4] * 9,
            back: [5] * 9,
        }
    end

    def rot(side)
        rot_side(side)

        case side
        when :front
            rot_perim(top: [6, 7, 8], right: [0, 3, 6], bottom: [6, 7, 8], left: [8, 5, 2])
        when :top
            rot_perim(back: [2, 1, 0], right: [2, 1, 0], front: [2, 1, 0], left: [2, 1, 0])
        when :right
            rot_perim(top: [8, 5, 2], back: [0, 3, 6], bottom: [0, 3, 6], front: [2, 5, 8])
        when :left
            rot_perim(top: [0, 3, 6], front: [0, 3, 6], bottom: [8, 5, 2], back: [8, 5, 2])
        when :back
            rot_perim(top: [2, 1, 0], left: [0, 3, 6], bottom: [2, 1, 0], right: [8, 5, 2])
        when :bottom
            rot_perim(back: [6, 7, 8], left: [6, 7, 8], front: [6, 7, 8], right: [6, 7, 8])
        end
    end

    private

    def clone_cell
        Marshal.load(Marshal.dump(@cells))
    end

    def rot_side(side)
        old = clone_cell

        @cells[side][0] = old[side][6]
        @cells[side][1] = old[side][3]
        @cells[side][2] = old[side][0]
        @cells[side][3] = old[side][7]
        @cells[side][5] = old[side][1]
        @cells[side][6] = old[side][8]
        @cells[side][7] = old[side][5]
        @cells[side][8] = old[side][2]
    end

    def rot_perim(**list)
        old = clone_cell

        4.times do |side_idx|
            3.times do |cell_idx|
                @cells[list.to_a[(side_idx + 1) % 4][0]][list.to_a[(side_idx + 1) % 4][1][cell_idx]] = old[list.to_a[side_idx][0]][list.to_a[side_idx][1][cell_idx]]
            end
        end
    end
end

class SolutionFinder
    SIDES = [:front, :top, :left, :right, :back, :bottom]
    MAX_TRY = 20
    SUCCESS_DISTANCE = 4

    def initialize
        @cube = Cube.new
        @cube_reference = Cube.new
        @cube_reference.freeze
    end

    def seek
        while true
            @cube = Cube.new
            steps = []
            MAX_TRY.times do |n|
                side = SIDES.sample
                dir = [1, 3].sample
                steps << [side, dir]

                dir.times { @cube.rot(side) }

                dist = distance
                if dist > 0 && dist <= SUCCESS_DISTANCE
                    puts "Potential algorithm in #{n} steps with distance #{dist}"
                    pp steps
                    HTMLPrinter.print(@cube.cells, steps, dist)
                    break
                end
            end
        end
    end

    def distance
        d = 0
        @cube_reference.cells.each do |side, cells|
            cells.each_with_index { |cell, idx| d += 1 if cell != @cube.cells[side][idx] }
        end
        d
    end
end

class HTMLPrinter
  class << self
    def print(cells, steps, distance)
      initialize_file_if_necessary

      File.open(filename, 'a') do |f|
        f.puts <<~HTML
          <div class="cube">
            <div class="half h1">
              <div class="side s1">
                <div class="row r1">
                  <div class="cell c1" style="background-color:#{colors[cells[:top][0]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:top][1]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:top][2]]}"></div>
                  <div style="clear: both"></div>
                </div>
                <div class="row r2">
                  <div class="cell c1" style="background-color:#{colors[cells[:top][3]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:top][4]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:top][5]]}"></div>
                  <div style="clear: both"></div>
                </div>
                <div class="row r3">
                  <div class="cell c1" style="background-color:#{colors[cells[:top][6]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:top][7]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:top][8]]}"></div>
                  <div style="clear: both"></div>
                </div>
              </div>
              <div class="side s2">
                <div class="row r1">
                  <div class="cell c1" style="background-color:#{colors[cells[:front][0]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:front][1]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:front][2]]}"></div>
                  <div style="clear: both"></div>
                </div>
                <div class="row r2">
                  <div class="cell c1" style="background-color:#{colors[cells[:front][3]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:front][4]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:front][5]]}"></div>
                  <div style="clear: both"></div>
                </div>
                <div class="row r3">
                  <div class="cell c1" style="background-color:#{colors[cells[:front][6]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:front][7]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:front][8]]}"></div>
                  <div style="clear: both"></div>
                </div>
              </div>
              <div class="side s3">
                <div class="row r1">
                  <div class="cell c1" style="background-color:#{colors[cells[:right][0]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:right][1]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:right][2]]}"></div>
                  <div style="clear: both"></div>
                </div>
                <div class="row r2">
                  <div class="cell c1" style="background-color:#{colors[cells[:right][3]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:right][4]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:right][5]]}"></div>
                  <div style="clear: both"></div>
                </div>
                <div class="row r3">
                  <div class="cell c1" style="background-color:#{colors[cells[:right][6]]}"></div>
                  <div class="cell c2" style="background-color:#{colors[cells[:right][7]]}"></div>
                  <div class="cell c3" style="background-color:#{colors[cells[:right][8]]}"></div>
                  <div style="clear: both"></div>
                </div>
              </div>
            </div>
          </div>
        HTML
      end
    end

    def colors
      [
        'lightgrey',
        'red',
        'green',
        'blue',
        'yellow',
        'orange',
      ]
    end

    def initialize_file_if_necessary
      return if File.exist?(filename)

      File.open(filename, 'w') do |f|
        f.puts <<~HEAD
          <style>
          .side {
            width: 186px;
          }
          .cell {
            width: 60px;
            height: 60px;
          }
          .row .cell {
            float: left;
            margin: 1px;
          }
          .side.s1 {
            transform: skewX(-45deg) translate(48px, 0px);
          }
          .side.s3 {
            transform: skewY(-45deg) translate(186px, -92px);
          }
          .side.s1 .cell {
            height: 30px;
          }
          .side.s3 .cell {
            width: 30px;
          }
          </style>
        HEAD
      end
    end

    def filename
      @filename ||= "/home/itarato/Desktop/rubik_result_#{Time.now.to_i}.html"
    end
  end
end

SolutionFinder.new.seek