我目前正在用python编写一个数独求解程序，只是为了好玩。这是我目前拥有的：
#!/usr/bin/env python
"""Reads in a file formatted with nine lines each of which has nine characters
corresponding to a sudoku puzzle. A blank is indicated by the value '0'
Eventually should output a solution to the input puzzle"""
import sys
class cell:
value = 0
"""Value of 0 means it is undetermined"""
def __init__(self, number):
self.value = number
self.possible = [2, 2, 2, 2, 2, 2, 2, 2, 2]
"""Possibility a given value can be the number. 0 is impossible, 1 is definite, 2 is maybe"""
def selfCheck(self):
"""Checks if the cell has only one possible value, changes the value to that number"""
if self.value == 0:
if self.possible.count(2) == 1:
"""If there's only one possible, change the value to that number"""
i = 1
for item in self.possible:
if item == 2:
self.value = i
self.possible[i-1] = 1
i+=1
def checkSection(section):
"""For any solved cells in a section, marks other cells as not being that value"""
for cell in section:
if cell.value != 0:
for otherCell in section:
otherCell.possible[cell.value-1] = 0
def checkChunk(chunk):
"""Checks a chunk, the set of rows, columns, or squares, and marks any values that are impossible for cells based on that
chunk's information"""
for section in chunk:
checkSection(section)
def selfCheckAll(chunk):
for section in chunk:
for cell in section:
cell.selfCheck()
cellRows = [[],[],[],[],[],[],[],[],[]]
cellColumns = [[],[],[],[],[],[],[],[],[]]
cellSquares = [[],[],[],[],[],[],[],[],[]]
infile = open(sys.argv[1], 'r')
"""Reads the file specified on the command line"""
i = 0
for line in infile:
"""Reads in the values, saves them as cells in 2d arrays"""
line = line.rstrip('\n')
for char in line:
row = i/9
column = i%9
newcell = cell(int(char))
cellRows[row].append(newcell)
cellColumns[column].append(newcell)
row = (row/3)*3
column = column/3
square = row+column
cellSquares[square].append(newcell)
i+=1
i = 0
while i<50:
checkChunk(cellRows)
checkChunk(cellColumns)
checkChunk(cellSquares)
selfCheckAll(cellRows)
i+=1
displayRow = []
for row in cellRows:
for cell in row:
displayRow.append(str(cell.value))
i = 0
while i < 9:
output1 = ''.join(displayRow[9*i:9*i+3])
output2 = ''.join(displayRow[9*i+3:9*i+6])
output3 = ''.join(displayRow[9*i+6:9*i+9])
print output1 + ' ' + output2 + ' ' + output3
if i%3 == 2:
print
i+=1
我的问题是：
i = 0
while i<50:
checkChunk(cellRows)
checkChunk(cellColumns)
checkChunk(cellSquares)
selfCheckAll(cellRows)
i+=1
我想运行代码，直到它检测到上一次迭代没有变化，而不是当前硬编码 50 次。这可能是因为不再有合乎逻辑的下一步（需要开始暴力破解值），或者难题已完全解决。无论哪种方式，我都需要一个我当前数据集的深层副本（比如 cellRows），以便与实际副本通过我的 checkChunk 函数时可能发生的变化进行比较。
Python中有这样的东西吗？（如果有更好的方法来检查我是否完成了，那也可以，尽管此时我更感兴趣的是是否可以进行深入比较。）
编辑 - 我尝试使用 copy.deepcopy。虽然这创建了一个很好的深层副本，但使用 '==' 检查两者之间的相等性总是返回 false。