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24 lines
433 B
Python
24 lines
433 B
Python
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class Stack:
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def __init__(self):
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self.stack = []
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self.top = 0
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def is_empty(self):
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return self.top == 0
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def push(self, item):
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if self.top < len(self.stack):
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self.stack[self.top] = item
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else:
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self.stack.append(item)
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self.top += 1
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def pop(self):
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if self.is_empty():
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return None
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else:
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self.top -= 1
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return self.stack[self.top]
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