Today's Challenge

https://leetcode.com/problems/basic-calculator/

Basic Calculator - LeetCode

계산기는 스택이 기본.. =_=

class Solution:
    def calculate(self, s: str) -> int:
        num, sign, st = 0, 1, [0]
        
        for c in s:
            if c.isdigit():
                num = num * 10 + int(c)
                
            elif c == ' ':
                continue
            
            elif c == '+':
                st[-1] += num * sign
                sign = 1
                num = 0
            
            elif c == '-':
                st[-1] += num * sign
                sign = -1
                num = 0
                
            elif c == '(':
                st.extend([sign, 0])
                sign = 1
                num = 0
                
            elif c == ')':
                last_num = (st.pop() + num * sign) * st.pop()
                st[-1] += last_num
                sign = 1
                num = 0
        
        return st[-1] + num * sign