最大数

from functools import cmp_to_key
def solve():
    def largestNumber(____):
        def compare(____):
            if a + b > b + a:
                return -____
            return ____
        nums = list(map(____))
        nums.sort(key=cmp_to_key(____))
        result = '____'.join(____)
        return '____' if result[____] == '____' else result
    print(largestNumber(____))