From: kevin cline <kevin.cline@...>
Date: 2007-11-11T06:15:00+09:00
Subject: Re: Looking for a Sudoku Algorithm to implement in Ruby

On Nov 10, 10:50 am, Victor Reyes <victor.re...@gmail.com> wrote:
> Hey,
>
> Did anyone know of a Sudoku algorithm, which I can use to implement a Ruby
> solution?

The Soduku puzzle can be solved in a few seconds by a very simple
backtracking algorithm:

  current_cell = first_empty_cell

  while true
    if put_next_possible_number_in_current_cell
      if all_cells_filled
        print_solution
        exit
      else
        current_cell = next_empty_cell
      end
    else if current_cell = first_empty_cell
      raise Exception.new("no solution")
    else
      current_cell = previous_empty_cell
  end