Is Sudoku Valid Python

PROGRAM TO CHECK IF GIVEN SUDOKU SOLUTION IS VALID OR NOT

# Function to check if all elements

# of the board[][] array store

# value in the range[1, 9]

def isinRange(board):

   

  N = 9

   

  # Traverse board[][] array

  for i in range(0, N):

    for j in range(0, N):

       

      # Check if board[i][j]

      # lies in the range

      if ((board[i][j] <= 0) or

          (board[i][j] > 9)):

        return False

       

  return True

 

# Function to check if the solution

# of sudoku puzzle is valid or not

def isValidSudoku(board):

   

  N = 9

   

  # Check if all elements of board[][]

  # stores value in the range[1, 9]

  if (isinRange(board) == False):

    return False

 

  # Stores unique value

  # from 1 to N

  unique = [False] * (N + 1)

 

  # Traverse each row of

  # the given array

  for i in range(0, N):

     

    # Initiliaze unique[]

    # array to false

    for m in range(0, N + 1):

      unique[m] = False

 

    # Traverse each column

    # of current row

    for j in range(0, N):

       

      # Stores the value

      # of board[i][j]

      Z = board[i][j]

 

      # Check if current row

      # stores duplicate value

      if (unique[Z] == True):

        return False

       

      unique[Z] = True

 

  # Traverse each column of

  # the given array

  for i in range(0, N):

     

    # Initiliaze unique[]

    # array to false

    for m in range(0, N + 1):

      unique[m] = False

 

    # Traverse each row

    # of current column

    for j in range(0, N):

       

      # Stores the value

      # of board[j][i]

      Z = board[j][i]

 

      # Check if current column

      # stores duplicate value

      if (unique[Z] == True):

        return False

       

      unique[Z] = True

 

  # Traverse each block of

  # size 3 * 3 in board[][] array

  for i in range(0, N - 2, 3):

     

    # j stores first column of

    # each 3 * 3 block

    for j in range(0, N - 2, 3):

       

      # Initiliaze unique[]

      # array to false

      for m in range(0, N + 1):

        unique[m] = False

 

      # Traverse current block

      for k in range(0, 3):

        for l in range(0, 3):

           

          # Stores row number

          # of current block

          X = i + k

 

          # Stores column number

          # of current block

          Y = j + l

 

          # Stores the value

          # of board[X][Y]

          Z = board[X][Y]

 

          # Check if current block

          # stores duplicate value

          if (unique[Z] == True):

            return False

           

          unique[Z] = True

           

  # If all conditions satisfied

  return True

 

# Driver Code

if __name__ == '__main__':

   

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

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

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

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

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

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

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

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

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

 

  if (isValidSudoku(board)):

    print("Valid")

  else:

    print("Not Valid")







OUTPUT

Valid

CREDITS: https://www.geeksforgeeks.org/check-if-given-sudoku-solution-is-valid-or-not/