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32 lines
801 B
Python
32 lines
801 B
Python
2 years ago
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class Stack(object):
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def __init__(self, maxlength=27):
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self.stack = []
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self.maxlength = maxlength
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self.top = 0
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def push(self, value): # 进栈
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self.stack.append(value)
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if self.top >= self.maxlength:
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for i in self.stack[:-27]:
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self.stack.remove(i)
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self.top += 1
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def pop(self): # 出栈
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if self.top == 0:
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raise StackEmptyException('Your stack is empty!')
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self.top -= 1
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el = self.stack[self.top]
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return el
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def is_empty(self): # 如果栈为空
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return bool(self.stack)
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def top(self):
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# 取出目前stack中最新的元素
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return self.stack[-1]
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class StackEmptyException(Exception):
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"""自定义一个栈空出异常"""
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pass
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