179. Largest Number

https://leetcode.com/problems/largest-number/

Problem

Given a list of non-negative integers nums, arrange them such that they form the largest number.

Note: The result may be very large, so you need to return a string instead of an integer.

Example 1:

Input: nums = [10,2]
Output: "210"

Example 2:

Input: nums = [3,30,34,5,9]
Output: "9534330"

Example 3:

Input: nums = [1]
Output: "1"

Example 4:

Input: nums = [10]
Output: "10"

Constraints:

• 1 <= nums.length <= 100

• 0 <= nums[i] <= 109

Solution

class Solution {
public:
    string largestNumber(vector<int>& nums) {
        auto comp = [](int a, int b) {
            string ab = to_string(a) + to_string(b);
            string ba = to_string(b) + to_string(a);
            return ab > ba;
        };
        sort(nums.begin(), nums.end(), comp);
        string num;
        for (const auto n: nums) num += to_string(n);
        return (num[0] == '0') ? "0" : num;
    }
};

• #math