110 lines
2.5 KiB
Python
110 lines
2.5 KiB
Python
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class Stack:
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def __init__(self):
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self.top = None
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@property
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def bottom(self):
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curr, last = self.top, None
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while curr:
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curr, last = curr.next, curr
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return last
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def push(self, obj):
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if not self.top:
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self.top = obj
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else:
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self.bottom.next = obj
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def pop(self):
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if not self.top:
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return None
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a, b, c = [self.top] + [None] * 2
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while a:
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a, b, c = a.next, a, b
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if c:
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c.next = None
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if c == self.top:
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self.top = None
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if self.top in [b, c]:
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self.top = None
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return b
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def get_data(self):
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result = []
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obj = self.top
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while obj:
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result.append(obj.data)
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obj = obj.next
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return result
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def __str__(self):
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return " -> ".join(self.get_data())
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class StackObj:
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def __init__(self, data=None):
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self.__next = None
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self.__data = data
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@property
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def data(self):
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return self.__data
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@data.setter
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def data(self, value):
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self.__data = value
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@property
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def next(self):
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return self.__next
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@next.setter
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def next(self, value):
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if isinstance(value, (self.__class__, None.__class__)):
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self.__next = value
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def __repr__(self):
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return f"{self.__class__.__name__}({self.data!r})"
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s = Stack()
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top = StackObj("obj_1")
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s.push(top)
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s.push(StackObj("obj_2"))
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s.push(StackObj("obj_3"))
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s.pop()
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res = s.get_data()
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assert res == ["obj_1", "obj_2"], f"метод get_data вернул неверные данные: {res}"
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assert s.top == top, "атрибут top объекта класса Stack содержит неверное значение"
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h = s.top
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while h:
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res = h.data
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h = h.next
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s = Stack()
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top = StackObj("obj_1")
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s.push(top)
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s.pop()
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assert s.get_data() == [], f"метод get_data вернул неверные данные: {s.get_data()}"
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n = 0
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h = s.top
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while h:
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h = h.next
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n += 1
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assert n == 0, "при удалении всех объектов, стек-подобная стурктура оказалась не пустой"
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s = Stack()
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top = StackObj("name_1")
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s.push(top)
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obj = s.pop()
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assert obj == top, "метод pop() должен возвращать удаляемый объект"
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