Question

我正在尝试在Python中创建一个使用depth-first“蛮力”来解决难题的数独拼图解算器。但是，在多次重新编码之后，我一遍又一遍地想出同样的错误。

我会尽可能清楚地解释问题 - 因为这是我与深度优先搜索相关的第一个问题，可能是我遗漏了一些明显的问题。

以下是剪切代码（在不需要细节的地方混合使用伪代码）：

def solvePuzzle(puzzle):
    <while the puzzle is still not solved>:
        <make a copy of the puzzle>
        <go through each unsolved box>: 
            <try to find the value of the box>
            <if the current solution is impossible, return to the parent branch>
        <if the copy of the puzzle is exactly the same as the puzzle now, no changes have been made, so its time to start branching into different possibilities>:      
            <pick a random box to guess the number of>
            <go through each possible value and run solvePuzzle() on that puzzle>:
                <if a solution is returned, return it>
                <else, try the next possible value>
    <return the puzzle>

这就像我可以做到的那样减少 - 对不起，如果它仍然有点读/混淆。

出于某种原因，即使将程序设置为solvePuzzle（）后，每个创建的谜题副本，它都会发现所有副本都是不可能的（不可能，我的意思是猜测中出现了错误）。这是不可能的，因为每个数字都在测试中！

Here's the full code（只有大约50行代码），如果不够清楚的话。

如果有人甚至建议为什么这不起作用，我会非常感激。

谢谢！

修改： As promised, here's the "isSolved()" method.

Answer 1

我强烈怀疑问题出现在这里：

# Go through each possibility in the branch until one solution is found
clone = deepcopy(puzzle)
values = clone[index / 9][index % 9]
for value in values:
    clone[index / 9][index % 9] = value
    branch = solvePuzzle(clone)
    # If a list is returned, it worked! Otherwise, try the next possibility
    if isinstance(branch, list):
        return branch

为每个候选值改变clone副本，并且在发现矛盾时不会恢复到半解决的拼图状态。试试这个：

# Go through each possibility in the branch until one solution is found
values = puzzle[index / 9][index % 9]
for value in values:
    clone = deepcopy(puzzle)
    clone[index / 9][index % 9] = value
    branch = solvePuzzle(clone)
    # If a list is returned, it worked! Otherwise, try the next possibility
    if isinstance(branch, list):
        return branch

如何解决深度优先的数独解决方案？

1 个答案: