为什么这个*不能正常工作？

Question

写了一个A *实现来解决8-puzzle游戏。由于某种原因，该算法适用于不太复杂的谜题。我尝试了最糟糕的案例拼图，它返回了非最佳结果。是我的启发式错误还是我的堆弹出错误的值，可能是错的？

最坏情况：

shell.sh

这是我的代码

[[8,6,7],[2,5,4],[3,0,1]]

节点类

def ast(board, isDraw):
    """ Computes the steps to solve the puzzle using A*
            RETURNS: Path, Depth of Node, Max Depth of graph, Number of Expanded nodes, time algorithm finished"""
    solvedBoard = [[0, 1, 2], [3, 4, 5], [6, 7, 8]]  # SolvedBoard
    maxDepth = 0
    nodesExpanded = 0

    open = list()
    opend = dict()
    closed = list()
    closedd = dict()

    # Find where 0 is on board
    for row in range(3):
        for column in range(3):
            if 0 == board[row][column]:
                posn = [row, column]

    root = Node(list(), board, posn, 0, f=0)
    heapq.heappush(open, root)
    opend[hash(root)] = root

    while len(open) > 0:
        node = heapq.heappop(open)
        del(opend[hash(node)])
        nodesExpanded += 1

        for child in node.getChildren():
            maxDepth = max(child.depth, maxDepth)
            if child.board == solvedBoard:
                finishedTime = time.clock()
                return (child.path, child.depth, maxDepth, nodesExpanded, finishedTime)
            else:
                if hash(child) in opend.keys() and opend[hash(child)] < child.f:
                    continue
                if hash(child) in closedd.keys() and closedd[hash(child)] < child.f:
                    continue
                heapq.heappush(open,child)
                opend[hash(child)] = child
        heapq.heappush(closed, node)
        closedd[hash(node)] = node
    finishedTime = time.clock()
    return ("There is no solution for this configuration of the board","?",maxDepth,nodesExpanded,finishedTime)