202 - 179 最大数

题目

给定一组非负整数，重新排列它们的顺序使之组成一个最大的整数。

示例 1:

输入: [10,2] 输出: 210

示例 2:

输入: [3,30,34,5,9] 输出: 9534330

说明: 输出结果可能非常大，所以你需要返回一个字符串而不是整数。

解答

就。根据第一位排序、再第二位排序，然后输出。

字符串

https://leetcode-cn.com/problems/largest-number/solution/zui-da-shu-by-leetcode/

官方看不懂的骚操作😂😂

class Compare(str):
    def __lt__(x, y):
        return x+y > y+x


class Solution:
    def largestNumber(self, nums: List[int]) -> str:
        largest_num = ''.join(sorted(map(str, nums), key=Compare))
        return '0' if largest_num[0] == '0' else largest_num

Runtime: 36 ms, faster than 73.50% of Python3 online submissions for Largest Number.

Memory Usage: 12.7 MB, less than 100.00% of Python3 online submissions for Largest Number.

数字

https://leetcode-cn.com/problems/largest-number/solution/python-ji-bai-999-bing-bu-shi-yong-ren-he-zi-fu-ch/

这个算法思路是，把数字变到小数点后面很多位数

比如12变成0.121212…，121变成0.121121121...

据此排序，就是结果了，直接拼成字符串即可

class Solution:
    def largestNumber(self, nums: List[int]) -> str:
        def bi(i):
            if i == 0:
                return 0
            s = 0
            k = i
            while i >= 1:
                i /= 10
                s += 1
            return k/(10**s-1)
        nums = sorted(nums, key=bi, reverse=True)
        if nums[0] == 0:
            return "0"
        return "".join([str(i) for i in nums])

Runtime: 36 ms, faster than 73.50% of Python3 online submissions for Largest Number.

Memory Usage: 12.8 MB, less than 100.00% of Python3 online submissions for Largest Number.