sample.unsolved.txt

096040001100060004504810390007950043030080000405023018010630059059070830003590007
105802000090076405200400819019007306762083090000061050007600030430020501600308900
005030081902850060600004050007402830349760005008300490150087002090000600026049503
096040001100060004504810390007950043030080000405023018010630059059070830003590007
105802000090076405200400819019007306762083090000061050007600030430020501600308900
005030081902850060600004050007402830349760005008300490150087002090000600026049503
290500007700000400004738012902003064800050070500067200309004005000080700087005109
080020000040500320020309046600090004000640501134050700360004002407230600000700450
608730000200000460000064820080005701900618004031000080860200039050000100100456200
370000001000700005408061090000010000050090460086002030000000000694005203800149500
000689100800000029150000008403000050200005000090240801084700910500000060060410000
030500804504200010008009000790806103000005400050000007800000702000704600610300500
000075400000000008080190000300001060000000034000068170204000603900000020530200000
300000000050703008000028070700000043000000000003904105400300800100040000968000200
302609005500730000000000900000940000000000109000057060008500006000000003019082040

sudoku.rb

# require 'debugger'

class Sudoku
  attr_reader :board, :clone_board

# --- INITIALIZE THE GAME ---
  def initialize(string)
    @string = string
    @new_string = ""
    @board = []
    @clone_board = []
    start_game
    total_solve
  end

# --- GAMEFLOW ---

  def start_game
    change_to_X
    clone_board
    # initialize_empty_board

  end


# --- SETTING UP THE BOARD ---
  def change_to_X
    @new_string = @string.gsub!("0", "X")
    @board = create_board(@new_string)
    # p @board
  end

  def create_board(string)
    temp_board = []
    start_board = string.split("")
    start_board.each_slice(9) {|array| temp_board << array}
    temp_board
  end

  def clone_board
    @clone_board = create_board(@new_string)
  end


  def view_board
    9.times do |x|
      puts "="*100 if x % 3 == 0
      9.times do |y|
        print "||".ljust(5) if y % 3 == 0
        print @board[x][y].to_s.ljust(10)
      end
     puts "\n"
    end
  end

  def view_clone_board
    9.times do |x|
      puts "="*100 if x % 3 == 0
      9.times do |y|
        print "||".ljust(5) if y % 3 == 0
        print @clone_board[x][y].to_s.ljust(20)
      end
     puts "\n"
    end
  end


# --- TOOLBELT ---
  # This method updates the cell value by replacing it on the grid
  def update_cell!(x_coordinate, y_coordinate, replace_with)
    new_board[x_coordinate][y_coordinate] = replace_with
  end

  # This method deletes the number from the possibilities of the array if called
  def deleter!(x_coordinate, y_coordinate, number)
  end

  # Checks if board is solved
  def solved?
  end


# --- SETTING POSSIBILITIES ---
  # This method will check if the current grid item is either a number or an X. Returns boolean
    # If true loop to next
    # Else: call method to fill with start-array

  def total_solve
    counter = 0
    until check_for_Xs?
      check_possibilities
      counter += 1
    end
    puts "It took #{counter} loops to figure out!"
    view_board
  end

  def check_for_Xs?
    9.times do |x|
      9.times do |y|
        return false if @board[x][y].match(/^X/)
      end   
    end
    true
  end  

  def check_possibilities
    (0...9).each do |x|
      (0...9).each do |y|
        if @board[x][y] == "X" 
          possible_nums = check_possible_nums(x,y, @board)
          @clone_board[x][y] = possible_nums
          flatten(x,y) if possible_nums.size == 1
        end
      end
    end 
    (0...9).each do |x|
      (0...9).each do |y| 
        check_square_single_outs(x,y)
      end
    end 
  end

 def flatten(x, y)
   @board[x][y] = @clone_board[x][y][0].to_s
  end 

  def check_possible_nums(row,col,board)
    good_nums = (1..9).to_a
    good_nums -= col_poss(board, col)
    good_nums -= row_poss(board, row)
    good_nums -= square_poss(board, row, col)
    good_nums
  end

  def row_poss(board, row)
    bad_nums = []
    9.times do |y|
      bad_nums << board[row][y].to_i if board[row][y] != "X"
    end
    bad_nums
  end

def col_poss(board, col)
  bad_nums = []
  9.times do |x|
    bad_nums << board[x][col].to_i if board[x][col] != "X"
  end
  bad_nums
end

def row_col_loop(board, x_offset, y_offset)
  bad_nums = []
  3.times do |x|
      3.times do |y|
       bad_nums << board[x + x_offset][y + y_offset].to_i if board[x+x_offset][y+y_offset] != "X"
      end
    end
    bad_nums
end

def square_poss(board, row, col)
  if row.between?(0,2)
    return row_col_loop(board, 0, 0) if col.between?(0, 2)
    return row_col_loop(board, 0, 3) if col.between?(3, 5)
    return row_col_loop(board, 0, 6) if col.between?(6, 8)
  elsif row.between?(3,5)
    return row_col_loop(board, 3, 0) if col.between?(0, 2)   
    return row_col_loop(board, 3, 3) if col.between?(3, 5)
    return row_col_loop(board, 3, 6) if col.between?(6, 8)   
  else
    return row_col_loop(board, 6, 0) if col.between?(0, 2)   
    return row_col_loop(board, 6, 3) if col.between?(3, 5)
    return row_col_loop(board, 6, 6) if col.between?(6, 8)      
  end
end

def check_square_single_looper(board, x_offset, y_offset)
  bad_nums = []

  # build bad nums array
  3.times do |x|
    3.times do |y|
      if board[x + x_offset][y + y_offset].kind_of?(Array)
        board[x + x_offset][y + y_offset].each {|elem| bad_nums << elem}
      end
    end    
  end

  # check against bad nums
  3.times do |x|
    3.times do |y|
      if board[x + x_offset][y + y_offset].kind_of?(Array)
        board[x + x_offset][y + y_offset].each_with_index do |three_deep_elem, index|
          if bad_nums.count(board[x+ x_offset][y+y_offset][index]) == 1
            @clone_board[x + x_offset][y + y_offset] = board[x + x_offset][y + y_offset][index].to_s         
            @board[x + x_offset][y + y_offset] = @clone_board[x + x_offset][y + y_offset]
          end
        end
      end
    end
  end

end

def check_square_single_outs(row, col, board = @clone_board)
  if row.between?(0,2)
    return check_square_single_looper(board, 0, 0) if col.between?(0, 2)
    return check_square_single_looper(board, 0, 3) if col.between?(3, 5)
    return check_square_single_looper(board, 0, 6) if col.between?(6, 8)
  elsif row.between?(3,5)
    return check_square_single_looper(board, 3, 0) if col.between?(0, 2)   
    return check_square_single_looper(board, 3, 3) if col.between?(3, 5)
    return check_square_single_looper(board, 3, 6) if col.between?(6, 8)   
  else
    return check_square_single_looper(board, 6, 0) if col.between?(0, 2)   
    return check_square_single_looper(board, 6, 3) if col.between?(3, 5)
    return check_square_single_looper(board, 6, 6) if col.between?(6, 8)      
  end
end

end

sudoku2 = Sudoku.new("096040001100060004504810390007950043030080000405023018010630059059070830003590007")
sudoku = Sudoku.new("105802000090076405200400819019007306762083090000061050007600030430020501600308900")
sudoku3 = Sudoku.new("005030081902850060600004050007402830349760005008300490150087002090000600026049503")
sudoku4 = Sudoku.new("096040001100060004504810390007950043030080000405023018010630059059070830003590007")
sudoku5 = Sudoku.new("105802000090076405200400819019007306762083090000061050007600030430020501600308900")
sudoku6 = Sudoku.new("005030081902850060600004050007402830349760005008300490150087002090000600026049503")
sudoku7 = Sudoku.new("290500007700000400004738012902003064800050070500067200309004005000080700087005109")
sudoku8 = Sudoku.new("080020000040500320020309046600090004000640501134050700360004002407230600000700450")
sudoku9 = Sudoku.new("608730000200000460000064820080005701900618004031000080860200039050000100100456200")
sudoku10 = Sudoku.new("370000001000700005408061090000010000050090460086002030000000000694005203800149500")
sudoku11 = Sudoku.new("000689100800000029150000008403000050200005000090240801084700910500000060060410000")
sudoku12 = Sudoku.new("030500804504200010008009000790806103000005400050000007800000702000704600610300500")
sudoku14 = Sudoku.new("300000000050703008000028070700000043000000000003904105400300800100040000968000200")
# sudoku15 = Sudoku.new("302609005500730000000000900000940000000000109000057060008500006000000003019082040") this one sucks too
# sudoku13 = Sudoku.nw("000075400000000008080190000300001060000000034000068170204000603900000020530200000") this one sucks