[Python] 수식 최대화

프로그래머스

2020 카카오 인턴쉽

 

https://school.programmers.co.kr/learn/courses/30/lessons/67257

프로그래머스

 

 

from collections import deque
from itertools import permutations 
def solution(expression):
    answer = 0
    ops = ['*', '+', '-']

    #분리, 스택 생성
    nums = []
    s = 0
    for idx, value in enumerate(expression):
        if value in ops:
            nums.append(expression[s:idx])
            nums.append(value)
            s = idx+1
    else:
        nums.append(expression[s:])

        stack = [deque(nums), deque()]
    print(stack)

    #expression에 없는 연산자 제거
    for op in ops:
        if op not in expression:
            ops.remove(op)
    possible = permutations(ops)
    print(possible)

    for case in possible:
        stacks = [deque(nums), deque()]
        t1 = 1
        for c in case:
            t1 = (t1+1) % 2 # 스택 토글 변수
            t2 = (t1+1) % 2
            while len(stacks[t1]):
                item = stacks[t1].popleft()
                if len(stacks[t2]) and stacks[t2][-1] == c:
                    c = stacks[t2].pop()
                    n = stacks[t2].pop()
                    item = str(eval(str(n)+c+str(item)))
                stacks[t2].append(item)

        result = stacks[len(ops)%2].pop()
        result = abs(int(result))
        answer = max(answer, result)

    #answer = 0
    return answer