sudoku_solution.rb

# Sudoku Solution Validator
# Write a function validSolution/ValidateSolution/valid_solution() that accepts a 2D array representing a Sudoku board, and returns true if it is a valid solution, or false otherwise. The cells of the sudoku board may also contain 0's, which will represent empty cells. Boards containing one or more zeroes are considered to be invalid solutions.

# The board is always 9 cells by 9 cells, and every cell only contains integers from 0 to 9.

def valid_solution(board)
  range = (1..9).to_a
  simple = board.flatten
  return false if simple.include?(0)
  
  board.each do |row|
    if row.sort == range
      return true
    else
      return false
    end
  end
end

puts "Should be true:"
puts valid_solution([[5, 3, 4, 6, 7, 8, 9, 1, 2], [6, 7, 2, 1, 9, 5, 3, 4, 8], [1, 9, 8, 3, 4, 2, 5, 6, 7], [8, 5, 9, 7, 6, 1, 4, 2, 3], [4, 2, 6, 8, 5, 3, 7, 9, 1], [7, 1, 3, 9, 2, 4, 8, 5, 6], [9, 6, 1, 5, 3, 7, 2, 8, 4], [2, 8, 7, 4, 1, 9, 6, 3, 5], [3, 4, 5, 2, 8, 6, 1, 7, 9]])

puts "Should be false:"
puts valid_solution([[5, 3, 4, 6, 7, 8, 9, 1, 2], [6, 7, 2, 1, 9, 0, 3, 4, 9], [1, 0, 0, 3, 4, 2, 5, 6, 0], [8, 5, 9, 7, 6, 1, 0, 2, 0], [4, 2, 6, 8, 5, 3, 7, 9, 1], [7, 1, 3, 9, 2, 4, 8, 5, 6], [9, 0, 1, 5, 3, 7, 2, 1, 4], [2, 8, 7, 4, 1, 9, 6, 3, 5], [3, 0, 0, 4, 8, 1, 1, 7, 9]])

puts "Should be true:"
puts valid_solution([[1, 3, 2, 5, 7, 9, 4, 6, 8], [4, 9, 8, 2, 6, 1, 3, 7, 5], [7, 5, 6, 3, 8, 4, 2, 1, 9], [6, 4, 3, 1, 5, 8, 7, 9, 2], [5, 2, 1, 7, 9, 3, 8, 4, 6], [9, 8, 7, 4, 2, 6, 5, 3, 1], [2, 1, 4, 9, 3, 5, 6, 8, 7], [3, 6, 5, 8, 1, 7, 9, 2, 4], [8, 7, 9, 6, 4, 2, 1, 5, 3]])

puts "Should be true:"
puts valid_solution([[1, 3, 2, 5, 7, 9, 4, 6, 8], [4, 9, 8, 2, 6, 1, 3, 7, 5], [7, 5, 6, 3, 8, 4, 2, 1, 9], [6, 4, 3, 1, 5, 8, 7, 9, 2], [5, 2, 1, 7, 9, 3, 8, 4, 6], [9, 8, 7, 4, 2, 6, 5, 3, 1], [2, 1, 4, 9, 3, 5, 6, 8, 7], [3, 6, 5, 8, 1, 7, 9, 2, 4], [8, 7, 9, 6, 4, 2, 1, 5, 3]])