25 lines
651 B
Python
25 lines
651 B
Python
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import math
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from collections import deque
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class Solution:
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def evalRPN(self, tokens: List[str]) -> int:
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compute = {
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'+': lambda a, b: a + b,
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'-': lambda a, b: a - b,
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'*': lambda a, b: a * b,
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'/': lambda a, b: math.trunc(a / b)
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}
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stack = deque()
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for token in tokens:
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if token.lstrip('-').isdigit():
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stack.append(int(token))
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else:
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right = stack.pop()
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left = stack.pop()
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stack.append(compute[token](left, right))
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return stack[-1]
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