class Calculator:
    def __init__(self):
        pass

    @staticmethod
    def infix_to_postfix(expression: list[str]):
        stack = []
        output = []
        precedence = {'+': 1, '-': 1, '*': 2, '/': 2}

        for token in expression:
            if token.isnumeric():
                output.append(token)
            elif token == '(':
                stack.append(token)
            elif token == ')':
                while stack and stack[-1] != '(':
                    output.append(stack.pop())
                stack.pop()  # 弹出左括号
            else:
                while stack and stack[-1] != '(' and precedence[token] <= precedence.get(stack[-1], 0):
                    output.append(stack.pop())
                stack.append(token)

        while stack:
            output.append(stack.pop())

        return output

    @staticmethod
    def calculate_postfix(expression: list[str]):
        stack = []

        for token in expression:
            if token.isnumeric():
                stack.append(int(token))
            else:
                operand2 = stack.pop()
                operand1 = stack.pop()

                result = 0
                if token == '+':
                    result = operand1 + operand2
                elif token == '-':
                    result = operand1 - operand2
                elif token == '*':
                    result = operand1 * operand2
                elif token == '/':
                    result = operand1 / operand2

                stack.append(result)

        return stack.pop()

    @staticmethod
    def str_to_list(equation: str):
        res = []
        curOp = ''

        for _chr in equation:
            if '0' <= _chr <= '9':
                curOp += _chr
            else:
                if len(curOp) > 0:
                    res.append(curOp)
                    curOp = ''
                res.append(_chr)

        if len(curOp) > 0:
            res.append(curOp)

        return res

    @staticmethod
    def calculate(equation: str):
        return Calculator.calculate_postfix(Calculator.infix_to_postfix(Calculator.str_to_list(equation)))


def main():
    test = Calculator()
    print(test.calculate('(2+3)*4-5+6'))


if __name__ == '__main__':
    main()