https://school.programmers.co.kr/learn/courses/30/lessons/42746

def solution(numbers):
answer = ''
numbers = list(map(str, numbers))
numbers.sort(key = lambda x : x*3,reverse=True) # 3번씩 반복하면 붙였을때 큰수 찾기 가능
for i in numbers:
answer += i
return str(int(answer))