문자열 스택

목표 문자열에서 정답을 추론하는 과정이 중요
https://school.programmers.co.kr/learn/courses/30/lessons/159994

def solution(cards1, cards2, goal):
    before_index1 = 0
    after_index1 = 0
    before_index2 = 0
    after_index2 = 0
    
    for i in goal:
        
        if i in cards1:
            before_index1 = after_index1
            after_index1 = cards1.index(i)
            if after_index1 - before_index1 != 1 and after_index1 != 0:
                return "No"
            
        if i in cards2:
            before_index2 = after_index2
            after_index2 = cards2.index(i)
            if after_index2 - before_index2 != 1 and after_index2 != 0:
                return "No"
    return "Yes"