Class: Sudoku::Solver

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

Overview

This class provides method for solving or checking solution of the Sudoku game.

Instance Method Summary collapse

Constructor Details

#initialize(grid) ⇒ Solver

Will initialize this solver with given grid. Exception is thrown if the given grid is not kind of Sudoku::Grid



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# File 'lib/sudoku/solver.rb', line 9

def initialize(grid)
  fail ArgumentError,
       'Invalid grid passed to solver' unless grid.is_a?(Grid)
  @grid = grid
end

Instance Method Details

#areas_violated? ⇒ Boolean

Will return true, if in some area of the grid are duplicit or illegal numbers. Returns false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 53

def areas_violated?
  [(0..2), (3..5), (6..8)].repeated_permutation(2).each do |x, y|
    cells = @grid.cells.select { |cell| cell.in_area(x, y) }
    return true if cells_violated?(cells)
  end
  false
end

#cells_violated?(cells) ⇒ Boolean

Will return true, if given set of cells does not contain duplicities in values other than 0.

  • cells set of cells to check.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 46

def cells_violated?(cells)
  values = cells.select { |x| x.value != 0 }.collect(&:value)
  values.uniq.size != values.size
end

#cols_violated? ⇒ Boolean

Will return true, if all cols are correctly solved.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 39

def cols_violated?
  (0..8).to_a.collect { |x|cells_violated?(@grid.get_col(x)) }.any?
end

#grid_filled? ⇒ Boolean

Will return true, if the grid is filled, which means, that all of the values are other than 0. False otherwise.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 29

def grid_filled?
  @grid.filled?
end

#rows_violated? ⇒ Boolean

Will return true, if all rows are correctly solved.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 34

def rows_violated?
  (0..8).to_a.collect { |x|cells_violated?(@grid.get_row(x)) }.any?
end

#rules_violated? ⇒ Boolean

Will check if the sudoku rules are violated, but the 0 value is ignored. Returns true if violated, false otherwise.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 17

def rules_violated?
  rows_violated? || cols_violated? || areas_violated?
end

#solved? ⇒ Boolean

Will return true, if all cells of the grid are filled and no Sudoku rule is violated.

Returns:

  • (Boolean) 


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# File 'lib/sudoku/solver.rb', line 23

def solved?
  !rules_violated? && grid_filled?
end