[Link] https://programmers.co.kr/learn/courses/30/lessons/42746
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
bool compare(int a, int b) {
string sa = to_string(a);
string sb = to_string(b);
return sa + sb > sb + sa;
}
string solution(vector<int> numbers) {
string answer = "";
sort(numbers.begin(), numbers.end(), compare);
if(numbers.at(0) == 0) return "0";
for(int num: numbers) answer += to_string(num);
return answer;
}