33 lines
657 B
Python
33 lines
657 B
Python
from typing import Generic, TypeVar
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T = TypeVar('T')
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class Stack(Generic[T]):
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def __init__(self):
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self.top: int = 0
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self.data: list[T] = []
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def push(self, value: T):
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self.data.append(value)
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self.top += 1
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def pop(self) -> T | None:
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if self.top > 0:
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self.top -= 1
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return self.data.pop()
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else:
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return None
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def peek(self) -> T | None:
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if self.top > 0:
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return self.data[self.top - 1]
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else:
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return None
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def is_empty(self) -> bool:
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return self.top == 0
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def size(self) -> int:
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return self.top
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