# Snake_ladder game using doubly linked list class Empty(Exception): """ Error attempting to access an element from an empty container.""" pass class DoublyLinkedBase: """Queue implementation using circularly linked list for storage.""" # -------------------------- nested Node class -------------------------- class _Node: """ Lightweight, nonpublic class for storing a doubly linked node. """ __slots__ = '_element', '_prev', '_next' # streamline memory usage def __init__(self, element, prev, next): # initialize node’s fields self._element = element # reference to user’s element self._prev = prev # previous node reference self._next = next # next node reference # ------------------------------- methods ------------------------------- def __init__(self): """ Create an empty list.""" self._header = self._Node(None, None, None) self._trailer = self._Node(None, None, None) self._header._next = self._trailer # trailer is after header self._trailer._prev = self._header # header is before trailer self._size = 0 # number of elements def __len__(self): """Return the number of elements in the list.""" return self._size def is_empty(self): """Return True if list is empty.""" return self._size == 0 def insert_between(self, e, predecessor, successor): """Add element e between two existing nodes and return new node.""" newest = self._Node(e, predecessor, successor) # linked to neighbors predecessor._next = newest successor._prev = newest self._size += 1 return newest def delete_node(self, node): """ Delete nonsentinel node from the list and return its element.""" predecessor = node._prev successor = node._next predecessor._next = successor successor._prev = predecessor self._size -= 1 element = node._element # record deleted element node._prev = node._next = node._element = None # deprecate node return element # return deleted element def display_board(self): current = self._header._next while current != self._trailer: print(current._element, end=" ") current = current._next print() def dice_roll_sequance(self, case): # not a random sequance if case == 1: self._dice_seq = [1, 5, 3] # 84 self.move_() print("case %d, ans = 84" % case) if case == 2: self._dice_seq = [4, 3, 6, 1] # 38 self.move_() print("case %d, ans = 38" % case) if case == 3: self._dice_seq = [5, 2, 6, 6, 3, 6, 5, 5] # 100 win self.move_() print("case %d, ans = 100 win" % case) if case == 4: self._dice_seq = [5, 2, 6, 6, 3, 6, 5, 1] # 61 self.move_() print("case %d, ans = 61 " % case) if case == 5: self._dice_seq = [5, 2, 6, 6, 3, 6, 5, 6] # 95 self.move_() print("case %d, ans = 95" % case) if case == 6: self._dice_seq = [1] # 38 self.move_() print("case %d, ans = 38" % case) if case == 7: self._dice_seq = [6, 1, 2] # 5 self.move_() print("case %d, ans = 5" % case) if case == 8: self._dice_seq = [6, 1, 2, 3] # 31 self.move_() print("case %d, ans = 31" % case) if case == 9: self._dice_seq = [1, 6, 6, 1, 6, 2] # 99 self.move_() print("case %d, ans =99" % case) def inistialize_board(self): for i in range(1, 101): if i == 2: self.insert_last(i, 36) elif i == 8: self.insert_last(i, 23) elif i == 17: self.insert_last(i, 6) elif i == 21: self.insert_last(i, 21) elif i == 33: self.insert_last(i, -28) elif i == 46: self.insert_last(i, 38) elif i == 51: self.insert_last(i, 16) elif i == 54: self.insert_last(i, -20) elif i == 63: self.insert_last(i, -47) elif i == 69: self.insert_last(i, i + 2) elif i == 71: self.insert_last(i, 20) elif i == 75: self.insert_last(i, 5) elif i == 80: self.insert_last(i, 19) elif i == 93: self.insert_last(i, -19) elif i == 96: self.insert_last(i, 1) elif i == 97: self.insert_last(i, -36) else: self.insert_last(i, 0) def move_(self): current = self._header or self._trailer if current is not None: for roll in self._dice_seq: for _ in range(roll): if current._next is not None and current._next._element is not None and current._next != self._trailer: current = current._next print("Moved to square", current._element) else: break if current is not None and current != self._trailer: self._header = current print("Current position:", current._element) else: print("Current position: None") else: print("Current position: None") def check_win(self): return self._header._element == 100 # Add this method inside the DoublyLinkedBase class def insert_last(self, square_id, move_shift): current = self._header._next while current: if current._element == square_id: current._element += move_shift # Ensure the circular behavior if current._element > 100: current._element = 200 - current._element print("Moved to square", current._element) self._header = current return current = current._next # Main dirver dl = DoublyLinkedBase() dl.inistialize_board() dl.display_board() for i in range(1, 10): dl.dice_roll_sequance(i)
我尝试过的：
我需要做什么修改才能不打印任何内容？（代码链接列表）
输出 ：
Current position: None case 1, ans = 84 Current position: None case 2, ans = 38 Current position: None case 3, ans = 100 win Current position: None case 4, ans = 61 Current position: None case 5, ans = 95 Current position: None case 6, ans = 38 Current position: None case 7, ans = 5 Current position: None case 8, ans = 31 Current position: None case 9, ans =99
解决方案1
首先，首先找出它打印“当前位置：无”的位置 – 有两个地方明确打印该内容，并且如果评估器为 current._element 曾是 None。 您可以使用调试器单步执行代码并找出答案： pdb — Python 调试器 — Python 3.12.1 文档[^] 如果您不知道如何使用它，将会有所帮助。
然后看看为什么它会达到这个位置，如果遵循什么路径以及为什么。 是什么导致事情发展成这样呢？ 哪些变量没有达到预期值？ 他们要做什么？ 它们应该包含什么？ 它们应该设置在哪里？ 为什么不是？
当您了解所有这些后，代码作者（即您）应该相当清楚问题是什么，并且您应该能够修复它。
但是让代码正常运行是作业的一个重要部分，除非您能够修复这样的简单代码，否则您不会学习如何修复复杂的代码！
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