python 数独游戏

网上看到一个python写的数独，很好玩：

import randomimport itertoolsfrom copy import deepcopydef make_board(m = 3):  numbers = list(range(1, m**2 + 1))  board = None  while board is None:    board = attempt_board(m, numbers)  return boarddef attempt_board(m, numbers):  n = m**2  board = [[None for _ in range(n)] for _ in range(n)]  for i, j in itertools.product(range(n), repeat = 2):    i0, j0 = i - i % m, j - j % m    random.shuffle(numbers)    for x in numbers:      if(x not in board[i]) and all(row[j] != x for row in board) and all(x not in row[j0:j0+m] for row in board[i0:i]):        board[i][j] = x        break    else:      return None  return boarddef print_board(board, m = 3):  numbers = list(range(1, m**2 + 1))  omit = 5  challange = deepcopy(board)  for i, j in itertools.product(range(omit), range(m ** 2)):    x = random.choice(numbers) - 1    challange[x][j] = None    spacer = "++---+---+---++---+---+---++---+---+---++"  print (spacer.replace('-', '='))  for i, line in enumerate(challange):    print("|| {0} | {1} | {2} || {3} | {4} | {5} || {6} | {7} | {8} ||".format(*(cell or ' ' for cell in line)))    if(i + 1) % 3 == 0:      print(spacer.replace('-', '='))    else:      print(spacer)  return challangedef print_answer(board):  spacer = "++---+---+---++---+---+---++---+---+---++"  print(spacer.replace('-','='))  for i, line in enumerate(board):    print("|| {0} | {1} | {2} || {3} | {4} | {5} || {6} | {7} | {8} ||".format(*(cell or ' ' for cell in line)))    if(i + 1) % 3 == 0:      print(spacer.replace('-','='))    else:      print(spacer)def is_full(challange, m = 3):  for i, j in itertools.product(range(m**2), repeat = 2):    if challange[i][j] is None:      return False  return Truedef cal_candidate(challange, x, y, m = 3):  candidate = range(1, m ** 2 + 1)  for i in range(m ** 2):    if challange[x][i] in candidate:      candidate.remove(challange[x][i])    if challange[i][y] in candidate:      candidate.remove(challange[i][y])  for i, j in itertools.product(range(m), repeat = 2):    x0, y0 = x - x % m, y - y % m    if challange[x0 + i][y0 + j] in candidate:      candidate.remove(challange[x0 + i][y0 + j])  return candidatedef least_candidate(challange, m = 3):  least, x, y = m ** 2, -1, -1  for i, j in itertools.product(range(m ** 2), repeat = 2):    if not challange[i][j]:      num = len(cal_candidate(challange, i, j))      if num < least:        least = num        x, y = i, j  return x, ydef solving_soduku(challange, m = 3):  if is_full(challange):    return challange  x, y = least_candidate(challange)  id = x * (m ** 2) + y  result = try_candidate(challange, id)  return resultdef try_candidate(challange, id, m = 3):  if is_full(challange):    return challange  x = id / (m ** 2)  y = id % (m ** 2)  while challange[x][y]:    id = (id + 1) % m ** 4    x = id / (m ** 2)    y = id % (m ** 2)  candidate = cal_candidate(challange, x, y)  if len(candidate) == 0:    return False  for i in range(len(candidate)):    challange[x][y] = candidate[i]    result_r = try_candidate(challange, (id + 1) % m ** 4)    if not result_r:      pass    else:      return challange  challange[x][y] = None  return False#Board = make_board()#print Board#challange = print_board(Board)#print_answer(Board)#result = solving_soduku(challange) #print_answer(result)   testing = [[8, None, None, None, None, None, None, None, None],           [None, None, 3, 6, None, None, None, None, None],           [None, 7, None, None, 9, None, 2, None, None],           [None,5 , None, None, None, 7, None, None, None ],           [None, None, None, None, 4, 6, 7, None, None],           [None, None, None, 1, None, None, None, 3, None],           [None, None, 1, None, None, None, None, 6, 8],           [None, None, 8, 5, None, None, None, 1, None],           [None, 9, None, None, None, None, 4, None, None]]result = solving_soduku(testing)print_answer(result)