Class: SudokuBuilder::Solver

Inherits:
Sudoku
  • Object
show all
Defined in:
lib/sudoku_builder/solver.rb

Instance Method Summary collapse

Methods inherited from Sudoku

#build_crg, #check?

Constructor Details

#initialize(sudoku) ⇒ Solver

Returns a new instance of Solver.



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# File 'lib/sudoku_builder/solver.rb', line 7

def initialize(sudoku)
  @sud = sudoku
  @pristine = sudoku
  @used = {
    0=> [], 1=> [], 2=> [], 3=> [], 4=> [], 5=> [], 6=> [], 7=> [], 8=> [],
    9=> [], 10=>[], 11=>[], 12=>[], 13=>[], 14=>[], 15=>[], 16=>[], 17=>[],
    18=>[], 19=>[], 20=>[], 21=>[], 22=>[], 23=>[], 24=>[], 25=>[], 26=>[],
    27=>[], 28=>[], 29=>[], 30=>[], 31=>[], 32=>[], 33=>[], 34=>[], 35=>[],
    36=>[], 37=>[], 38=>[], 39=>[], 40=>[], 41=>[], 42=>[], 43=>[], 44=>[],
    45=>[], 46=>[], 47=>[], 48=>[], 49=>[], 50=>[], 51=>[], 52=>[], 53=>[],
    54=>[], 55=>[], 56=>[], 57=>[], 58=>[], 59=>[], 60=>[], 61=>[], 62=>[],
    63=>[], 64=>[], 65=>[], 66=>[], 67=>[], 68=>[], 69=>[], 70=>[], 71=>[],
    72=>[], 73=>[], 74=>[], 75=>[], 76=>[], 77=>[], 78=>[], 79=>[], 80=>[]
  }
end

Instance Method Details

#solve ⇒ Object

solve any given sudoku. If the sudoku is empty, it will build a complete one.



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# File 'lib/sudoku_builder/solver.rb', line 24

def solve
  t = 0 ; o = 0 ;
  direction = true ; key = 0        # main key variable.
  loop do
    if @sud[key].class == Array       # skips pre-filled numbers.
      c = [] ; r = [] ; g = []        # build values for current grid, row, column.
      build_crg(key,c,r,g,@sud)       # updates the relevant variables for check.
      @sud[key] = []                  # makes a fresh possibilities array.
      for i in 1..9
        if check?(i, c,r,g) &&
            !@used[key].include?(i)
          @sud[key] << i
        end
      end
      if @sud[key].count == 0         # backtrack if no possibilities.
        key -= 1
        direction = false
      else
        use = @sud[key].sample        # pick a random possibility.
        @sud[key]   = [use]           # uses the possibility.
        @used[key] << use             # also puts it into the used array.
        key += 1
        direction = true
      end
    elsif @sud[key].class == Fixnum
      direction ? key += 1 : key -= 1 # backt or forward track based on current direction.
    end
    if key == 0 || t > 104 ||
            key == 1 && t > 3         # resets everything if we've reached a high amount
      @sud = @pristine.dup            # of run throughs, or the key has wound down to 0.
      @used.each do |k,v|
        @used[k] = []
      end
      key = 0 ; t = 0
      direction = true
    end
    break if key == 81                # break if we've reached the last value.
    t += 1 ; o += 1                   # add the reporting variables
    break if o > 1000000              # there is the possibility to be given an
  end
  Builder.new(@sud)
end