LeetCode题解(0150)：逆波兰表达式求值(Python)

题目：​​原题链接​​（中等）

标签：栈

LeetCode的Python执行用时随缘，只要时间复杂度没有明显差异，执行用时一般都在同一个量级，仅作参考意义。

解法一：

def evalRPN(self, tokens: List[str]) -> int:
    stack = []
    for token in tokens:
        if token == "+":
            b = stack.pop()
            a = stack.pop()
            stack.append(a + b)
        elif token == "-":
            b = stack.pop()
            a = stack.pop()
            stack.append(a - b)
        elif token == "*":
            b = stack.pop()
            a = stack.pop()
            stack.append(a * b)
        elif token == "/":
            b = stack.pop()
            a = stack.pop()
            stack.append(int(a / b))
        else:
            stack.append(int(token))

    return stack[0]