Excel 表列序号 最大数

class Solution:
    def titleToNumber(self, s: str) -> int:
        return sum(26**i*(ord(num)-64) for i ,num in enumerate(s[::-1]))

class LargestNumKey(str): #自定义排序__lt__函数
    def __lt__(x,y):
        return x+y > y+x
class Solution:
    def largestNumber(self,nums):
        largest_num = ''.join(sorted(map(str,nums), key = LargestNumKey))
        return '0' if largest_num[0]=='0' else largest_num