[프로그래머스] 여행경로 - Python

programmers.co.kr/learn/courses/30/lessons/43164

코딩테스트 연습 - 여행경로

def solution(tickets):
    answer = []
    
    tickets.sort(reverse=True)
    routes = {}
    
    for t1, t2 in tickets:
        if t1 in routes:
            routes[t1].append(t2)
        else:
            routes[t1] = [t2]
            
    stack = ['ICN']
    
    while stack:
        top = stack[-1]
        if top not in routes or len(routes[top]) == 0:
            answer.append(stack.pop())
        else:
            stack.append(routes[top].pop())
            
    answer.reverse()
        
    return answer