# 처음에 bfs로 풀려고 했으나 백트래킹이 안되므로def solution(tickets): result = [] obj = {} for ticket in tickets: obj.setdefault(ticket[0], []).append(ticket[1]) for v in obj.values(): v.sort() queue = dq(["ICN"]) last = "" while queue: current = queue.popleft() result.append(current) if not obj.get(current): break for next in obj[current]:..