Sudoku validator first version

loader.rb

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+
+require_relative 'sudoku'
+
+class Loader	
+
+    def self.load(path)
+    	grid = Array.new()
+    	File.open(path) do |f|
+        	f.each_line do |line|
+                # removes the vertical separator | and replaces it with a space 
+    			line = line.gsub('|', ' ') 
+                # the lines containing a + are horizontal separators, they are skipped
+            	if !line.include? '+'   
+            		grid << line.split(" ")	
+            	end
+          	end 	
+        end
+        return Sudoku.new(grid)
+    end
+
+end

sudoku.rb

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+class Sudoku
+
+	attr_reader :valid, :complete
+
+	def initialize(grid)  
+    	@grid = grid  
+    	@complete = nil
+    	@valid = nil 
+    	validate_grid
+	end 
+
+	protected
+	def validate_row(line_number)
+		line = @grid[line_number]
+		validate(line)
+	end
+
+	def validate_column(column_number)
+		# we are arranging all elements of the column in a single array fot the validation
+		line = Array.new()
+		@grid.each do |l|
+			line << l[column_number]
+		end
+		validate(line)
+	end
+
+	def validate_subgrid(subgrid_number)
+		# Each sudoku subgrid was assigned a subgrid_number as follow 
+		# 0 | 1 | 2
+		# 3 | 4 | 5
+		# 6 | 7 | 8 
+		# (i,j) is the upper left element of the subgrid 
+		i = (subgrid_number / 3) * 3
+		j = (subgrid_number - i) * 3
+
+		# we are arranging all elements of the sub grid in a single array for the validation
+		line = Array.new()
+		for k in 0..2
+			line += @grid[i+k][j..j+2]
+		end
+		validate(line)
+	end
+
+	# validates wether a given array of 9 elements contains a distinct sublist of numbers from 1 to 9
+	def validate(line)
+		check = Array.new(9)
+		line.each do |element|
+			element = element.to_i 
+			# Any non numerical element will return 0 
+			if element == 0 
+				@complete = false
+			else
+				if check[element - 1] != nil
+					@valid = false
+				else
+					check[element - 1] = 1
+				end
+			end	
+		end
+	end
+
+	def validate_grid
+		for i in 0..8
+			validate_row(i)
+			validate_column(i)
+			validate_subgrid(i)
+		end 
+		if @valid == nil
+			@valid = true
+		end
+		if @complete == nil
+			@complete = true
+		end
+	end
+
+end

sudoku_validator.rb

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+require_relative 'loader'
+require_relative 'sudoku'
+
+def answer(sudoku)
+	answer = "This Sudoku is " + ( sudoku.valid ? "valid" : "invalid") + " and " + (sudoku.complete ? "complete" : "incomplete") + "."
+	puts answer
+end
+
+ARGV.each do|a|
+	sudoku = Loader.load(a)
+  	answer(sudoku)
+end
+
+
+
+