Sudoku Solver 1 - Appendix 1 #blog #bernard

display_grid.py

def display_grid(grid, coords=False):
	"""
	Displays a 9x9 soduku grid in a nicely formatted way.

	Args:
		grid (str|dict|list): A string representing a Sudoku grid. Valid characters are digits from 1-9 and empty squares are
			specified by 0 or . only. Any other characters are ignored. A `ValueError` will be raised if the input does
			not specify exactly 81 valid grid positions.
			Can accept a dictionary where each key is the position on the board from A1 to I9.
			Can accept a list of strings or integers with empty squares represented by 0.
		coords (bool): Optionally prints the coordinate labels.
	Returns:
		str: Formatted depiction of a 9x9 soduku grid.
	"""
	if grid is None or grid is False:
		return None

	all_rows = 'ABCDEFGHI'
	all_cols = '123456789'
	null_chars = '0.'

	if type(grid) == str:
		grid = parse_puzzle(grid)
	elif type(grid) == list:
		grid = parse_puzzle(''.join([str(el) for el in grid]))

	width = max([3, max([len(grid[pos]) for pos in grid]) + 1])
	display = ''

	if coords:
		display += '   ' + ''.join([all_cols[i].center(width) for i in range(3)]) + '|'
		display += ''.join([all_cols[i].center(width) for i in range(3, 6)]) + '|'
		display += ''.join([all_cols[i].center(width) for i in range(6, 9)]) + '\n   '
		display += '--' + ''.join(['-' for x in range(width * 9)]) + '\n'

	row_counter = 0
	col_counter = 0
	for row in all_rows:
		if coords:
			display += all_rows[row_counter] + ' |'
		row_counter += 1
		for col in all_cols:
			col_counter += 1
			if grid[row + col] in null_chars:
				grid[row + col] = '.'

			display += ('%s' % grid[row + col]).center(width)
			if col_counter % 3 == 0 and col_counter % 9 != 0:
				display += '|'
			if col_counter % 9 == 0:
				display += '\n'
		if row_counter % 3 == 0 and row_counter != 9:
			if coords:
				display += '  |'
			display += '+'.join([''.join(['-' for x in range(width * 3)]) for y in range(3)]) + '\n'

	print(display)
	return display

puzzles.py

# Easy Sudoku Puzzle
puzzle1 = """
1  .  5 | .  7  . | 4  .  .
.  8  . | 2  .  . | .  .  .
7  2  4 | .  .  1 | .  .  6
---------+---------+---------
.  .  . | 3  2  5 | .  .  .
2  3  7 | .  .  . | 1  4  5
6  .  . | 4  1  7 | .  .  .
---------+---------+---------
8  .  . | 1  .  . | 6  2  4
.  .  . | .  .  3 | .  5  .
.  .  1 | .  4  . | 3  .  9
"""

# Arto Inkala's 2012 Puzzle
puzzle = """
8  .  . | .  .  . | .  .  .
.  .  3 | 6  .  . | .  .  .
.  7  . | .  9  . | 2  .  .
---------+---------+---------
.  5  . | .  .  7 | .  .  .
.  .  . | .  4  5 | 7  .  .
.  .  . | 1  .  . | .  3  .
---------+---------+---------
.  .  1 | .  .  . | .  6  8
.  .  8 | 5  .  . | .  1  .
.  9  . | .  .  . | 4  .  .
"""

validate_sudoku.py

def validate_sudoku(puzzle):
	"""Checks if a completed Sudoku puzzle has a valid solution."""
	
    if puzzle is None:
		return False
      
	coords, groups, all_units = sudoku_reference()
	full = [str(x) for x in range(1, 10)]  # Full set, 1-9 as strings
    
	# Checks if all units contain a full set
	return all([sorted([puzzle[cell] for cell in unit]) == full for unit in all_units])