Sudoku solver

An OOP sudoku solver written purely in Ruby, with no dependencies. Tested on two different puzzles (very easy and moderate)

Run the tests

rspec

Using this as a library

It's possible, you can require it where needed, and then call Sudoku::Solver.solve(grid), where grid is a 2 dimensional array of numbers, with nil for empty squares, eg.

require "./lib/sudoku_solver"

solver = Sudoku::Solver.new [
  [ 4 ,nil, 6 ,    5 ,nil,  2,    8 ,nil, 9 ],
  [nil,nil,nil,   nil, 4 ,nil,   nil, 3 ,nil],
  [nil,nil,nil,   nil,nil,nil,   nil,nil, 5 ],

  [ 6 ,nil,nil,    8 ,nil,nil,    1 ,nil,nil],
  [ 5 ,nil,nil,   nil, 7 ,nil,   nil, 8 ,nil],
  [ 3 ,nil, 2 ,    9 ,nil, 4 ,   nil, 6 ,nil],

  [nil, 2 ,nil,    6 ,nil,nil,    3 ,nil, 1 ],
  [nil,nil,nil,   nil,  5 ,nil,  nil,nil,nil],
  [ 8 , 3 ,nil,   nil,  9 ,nil,  nil,nil, 2 ],
]
solver.solve # returns same grid, but with nils filled in