Sudoku: Difference between revisions

=={{header|Crystal}}==

Based on the Java implementation presented in the video "[https://www.youtube.com/watch?v=mcXc8Mva2bA Create a Sudoku Solver In Java...]".

<lang ruby>GRID_SIZE = 9

def isNumberInRow(board, number, row)

board[row].includes?(number)

end

def isNumberInColumn(board, number, column)

board.any?{|row| row[column] == number }

end

def isNumberInBox(board, number, row, column)

localBoxRow = row - row % 3

localBoxColumn = column - column % 3

(localBoxRow...(localBoxRow+3)).each do |i|

(localBoxColumn...(localBoxColumn+3)).each do |j|

return true if board[i][j] == number

end

end

false

end

def isValidPlacement(board, number, row, column)

return !isNumberInRow(board, number, row) &&

!isNumberInColumn(board, number, column) &&

!isNumberInBox(board, number, row, column)

end

def solveBoard(board)

board.each_with_index do |row, i|

row.each_with_index do |cell, j|

if(cell == 0)

(1..GRID_SIZE).each do |n|

if(isValidPlacement(board,n,i,j))

board[i][j]=n

if(solveBoard(board))

return true

else

board[i][j]=0

end

end

end

return false

end

end

end

return true

end

def printBoard(board)

board.each_with_index do |row, i|

row.each_with_index do |cell, j|

print cell

print '|' if j == 2 || j == 5

print '\n' if j == 8

end

print "-"*11 + '\n' if i == 2 || i == 5

end

print '\n'

end

board = [

[7, 0, 2, 0, 5, 0, 6, 0, 0],

[0, 0, 0, 0, 0, 3, 0, 0, 0],

[1, 0, 0, 0, 0, 9, 5, 0, 0],

[8, 0, 0, 0, 0, 0, 0, 9, 0],

[0, 4, 3, 0, 0, 0, 7, 5, 0],

[0, 9, 0, 0, 0, 0, 0, 0, 8],

[0, 0, 9, 7, 0, 0, 0, 0, 5],

[0, 0, 0, 2, 0, 0, 0, 0, 0],

[0, 0, 7, 0, 4, 0, 2, 0, 3]]

printBoard(board)

if(solveBoard(board))

printBoard(board)

end

</lang>

{{out}}

<pre>

702|050|600

000|003|000

100|009|500

-----------

800|000|090

043|000|750

090|000|008

-----------

009|700|005

000|200|000

007|040|203

732|458|619

956|173|824

184|629|537

-----------

871|564|392

643|892|751

295|317|468

-----------

329|786|145

418|235|976

567|941|283

</pre>